I thought it would be interesting to see what 3DS games people had, and maybe a brief summary of what you think of each game. This includes retail and downloadable title. Not counting built-in stuff like Face Raiders or Mii Plaza, and not counting apps like Pokedex 3D or Netflix. I'll start...

Pilotwings Resort - fun, but needs more content
Super Street Fighter IV 3D Edition - challenging, lots of content, looks good
nintendogs + cats - decent sequel, gets boring after a while
The Legend of Zelda: Ocarina of Time 3D - looks great, lots of fun, 3D is cool
Tom Clancy's Ghost Recon: Shadow Wars - lots of content, challenging but engaging, 3D is nothing special
Super Monkey Ball 3D - controls work well, but otherwise a very disappointing game
Bit.Trip Saga - great compilation, addicting, good music
Star Fox 64 3D - looks great especially in 3D, fun game
Tetris Axis - lots of different modes, pretty fun and online play is nice
Super Mario 3D Land - one of my favorite Mario titles, controls are great, 3D is awesome
Mario Kart 7 - my favorite Mario Kart and favorite 3DS game, 3D is great, tons of fun especially online, lots of content
Steel Diver - interesting concept, neat controls, short on content
Resident Evil: Revelations - looks great and 3D is neat, very engaging game, controls well
Kid Icarus: Uprising - tons of content, 3D is great, very fun to play, some controls work great and others are decent
Spirit Camera: The Cursed Memoir - interesting concept, short on content, AR stuff doesn't always work properly
3D Classics: Xevious - 3D is neat, simple but fun, challenging
3D Classics: Excitebike - 3D is neat, fun game, short on content
3D Classics: Kirby's Adventure - 3D is nothing special, easy but fun
3D Classics: Kid Icarus - challenging, 3D doesn't really add much
Ketzal's Corridors - simple yet addicting, plenty of content, 3D looks nice
Zen Pinball 3D - 3D is nothing special, simple but fun content
Marvel Pinball 3D - 3D is nothing special, simple but fun content
Mutant Mudds - challenging, 3D looks neat, fun and interesting
Freakyforms: Your Creations, Alive! - lots of creative abilities, but rather boring
Pushmo - interesting concept, plenty of content, quite challenging

I'll edit in my stuff on all the Virtual Console titles I have later.

In case you're curious, Mario Kart 7 is my most played title, followed by Ocarina of Time 3D and then Super Mario 3D Land.

Wow. That's quite a bit.

3DS Games
Metal Gear Solid Snake Eater 3D: The best 3DS title I've played, too bad it just happens to be a remake
Zelda Ocarina of Time 3D: Another good remake, I just wish there was a new Zelda adventure to play instead
Super Mario 3D Land: Really enjoyed this
Pilotwings Resort: Pretty good, nice 3D effects and some fun challenges, just not enough content
Super Street Fighter IV 3D: Probably my most played launch title
Mario Kart 7: Not a huge fan of the new additions, but it still feels like Mario Kart has always been, which is nice

eShop Games
Pushmo: This was a fun puzzle, but I didn't play much
Sakura Samurai: Didn't play this that much, it just didn't seem too special
3D Classics Excitebike: Always loved Excitebike, and happy to play it again
3D Classics Xevious: Another classic that I played long ago

All my Virtual Console titles are just the free ones for early buyers. I probably won't buy any more eShop titles, since nothing really attracts me. My next 3DS game will be Paper Mario, most likely. My next DS game (and probably last) will be Pokemon Black 2. Next year I'm excited for Luigi's Mansion and Animal Crossing, but I don't really know what else is coming.

I have put 31 hours into Ocarina of Time, 19 hours into Friend List (how the hell does it calculate that? I never open it!), and 15 into MGS. I just realized that I need to play MK7 more often.

Kid Icarus: Uprising: I bought this on a whim and I'm really glad I did. Excellent replay value.
Ocarina of Time 3D: Probably the main reason I wanted a 3DS. I am glad I finally was able to play through Master Quest.
Mario Kart 7: Not sure if I like it better than Mario Kart DS but that may change if I spend a little more time with it. The online play is much better than Mario Kart Wii.
Resident Evil: Revelations: Excellent game, definitely one of my favorite RE games, I wish it used the gyro controls for the aiming.
Ridge Racer 3D: I need to spend more time with this but I have fond memories of the RR series and this game delivers the same classic game play.

Samurai Sword Destiny: I was just on the eShop and looking for something new, this game kinda blows, it's way too repetitive, I'll finish it eventually.
Game Boy Donkey Kong: Got this through a Club Nintendo offer, decent I need to spent more time with it.
3D Classics Kid Icarus: excellent game bosses are not that challenging though.
Kid Icarus: Of Myths and Monsters: Pretty much a rehash of Kid Icarus but it fixed the problem of the bosses being too easy.
Link's Awakening DX: Finally was able to have a system to play this game on uninterrupted.
Metriod II: Return of Samus: A little linear for a Metriod title (not nearly as much as Other M) but still really fun.
Sonic Triple Trouble: I had this game as a kid and played it more than any of the other Game Gear titles I had, it's still great.
Super Mario Land: It was cheap and I'm nowhere near a game store, beat it on a slow day at work in about an hour. Decent.
Super Mario Land 2: 6 Golden Coins: Got it for the same reason Super Mario Land, this is a much better game.
3D Classics Urban Champion: This was another Club Nintendo offer, it's pretty repetitive but a good game to play for about 5 minutes at a time.
Warioland: Super Mario Land 3: I'm in the process of beating this, I have never played a Warioland game so it seemed appropriate to start here.

I also have some DSiware games that I transferred over but I didn't feel the need to list those as well.

I'll go in order (strike outs are ones I already sold off):
Retail
Ocarina of Time 3D - awesome remake with additional features (master quest, boss battles)
Thor - basic brawler, wasn't very enjoyable. Sold it quickly (hence the strikeout).
Super Mario 3D Land - very fun game, just way too easy (I had 100% before Mariokart 7 came out)
Mariokart 7 - best Mariokart game yet. Multiplayer is awesome, the courses are well designed and most of them are enjoyable.
Tetris Axis - pretty fun tetris game, but missing some of the fun modes from the DS version. Haven't played Multiplayer yet (@Darkwish/Hattrick!)
Cave Story 3D - same as the DSiWare game, just better graphics. Nothing special, wasn't anything new.
Resident Evil Revelations - decent game, but felt boring and slow paced. Graphics were superb though.
Kid Icarus Uprising - Very enjoyable game with awesome multiplayer and has lots of replay value.
Mario Tennis Open - decent game, has bad online play (had plenty of lag, and MANY people drop out when you're either winning, or about to receive the trophy, which denies you of the trophy)

I need to add in my virtual content in my edit. I was almost done this morning, but my computer decided to restart while I was typing and closed the browser.

Super Street Fighter IV 3D
The Legend of Zelda: Ocarina of Time 3D
Star Fox 64 3D
Mario Kart 7
Super Mario 3D Land
Bit Trip Saga
LEGO Pirates of the Caribbean
Assault Horizon Legacy
Tetris Axis
Mario Tennis Open
3D Classics: Excitebike
Pushmo
Mutant Mudds
Colors! 3D
Order Up!!
Bomb Monkey
Burger Time Deluxe
Planet Crashers
New Super Mario Bros. 2

All the 3DS Ambassador NES and GBA games

*This list does not include any of my DSiWare games.

Alright time for the long list:

Dillon's Rolling Western - decent tower defense game, need to play more
Touch Tank Battle 3D - very fun tank game. Reminds me of the Wii Play game (which was amazing!).
Zelda 4 Swords - okay solo game, haven't played much since the saving is too limiting.
Metroid 2 - fun Metroid game, need to finish replaying
Kid Icarus Myths and Legends - similar to the first, but just started playing
Pushmo - Incredibly fun puzzle game. Loved it!
FreakyForms - okay game, wish it was more enjoyable to play with the forms and didn't have the limited time.
Mutant Mudds - awesome platformer game, fun with some difficulty, recommended!
VVVVVV - love the classic art style, and has plenty of difficulty to 100% it. Very fun game.
3D Classic Excitebike: 3D is okay, wasn't a huge fan of the original, got it for free.
7 Wonders II - a bejewled clone that is okay. Gets boring and repetitive.
Marvel Pinball 3D - decent pinball game, not a huge Marvel fan.
Bomb Monkey - a very fun puzzle game. Needs leaderboards and online multiplayer.
Mighty Switch Force - another fun platforming game. The difficulty is high to 100% this one too.
Cave Story - fun adventure game with classic graphics and gameplay.
March of the Minis - fun puzzle game, mostly pretty easy though.
3D Classic Kid Icarus - same as the NES with some 3D effects and added backgrounds - still a fun game though.
All 10 GBA games - mostly unplayed since they came later than originally expected. Ones that I have played or same as originals (that I played). Haven't played most of the originals.
All 10 NES games - some are fun, some are updated, mostly the same as the originals. Dislike a few of them.
Super Mario Land 2 - fun Mario game, interesting with Wario as the villain.
Mega Man: Dr Wily's Revenge - interesting Mega man game with robot masters from 1 & 2 on the NES
Link's Awakening DX - Still fun to replay with the different items to use.
Super Mario Land - way too short, but fun.
Kirby's Dream Land - pretty fun, also somewhat short.

Super Street Fighter IV 3D
Mario Kart 7
Super Mario 3D Land
Bit Trip Saga
Mario Tennis Open
3D Classics: Excitebike
Colors! 3D
Order Up!!
Bomb Monkey
Burger Time Deluxe
Planet Crashers
New Super Mario Bros. 2

Super street fighter iv 3d
Nintendo dogs +cats
Mariokart 7
Mario and sonic at the london 2012 Olympic games
New super Mario bros 2
And for retail
Dillons rolling western

Retail: kid Icarus uprising ( excellent game high replay value)
The sims 3 ( decent game could have been better )
New super mario bros 2 ( one of my favorite 3ds games,
Scribblenauts. Unlimited ( the best game in the series)
Asphalt 3d ( not as bad as people think)
Pilotwings resort ( pretty addictive)
Street fighter ( as good as the console version)
Jaws ( an ok game)

Virtual console: super mario bros
Megaman
Mario six golden coins
Metroid 2 return of samus

i just got a 3ds so all i have is
Super Street Fighter 4
Mario kart 7
Asphalt 3d
Transformers Dark of the moon stealth attack
Metroid 2 return of samus
Brain games

Check out Kid Icarus Uprising, that's an awesome game. If you like adventure RPGs, check out Kingdom Hearts 3D and Ocarina of Time 3D.

New Super Mario Brothers 2 is also pretty solid.

OoT Zelda
SM3D Land
Mariokart 7
Nintendogs + Cats


DS games:
Kirby's mass attack( epic freaking game)
Kirby super star ultra