I just finished Legend of Zelda: Ocarina of Time 3D and I loved Master Quest.
I'm not a fan of fighting games especially since no one else I know has a 3DS and... it's not that fun playing multiplayer online because they're likely better at it then me. Plus, it's best when you have a friend to play it with. I'm not a fan of casual games like Nintendogs. I like puzzle games but... I don't think I'm willing to pay $30-40 on such a title. And I'm not a fan of Starfox.
I have from August to December... to find a game. I have multiple DS games to play too, however.
I live in the United States... I love RPGs however and it's been some time since I played a tactical RPG or a good action RPG, I was thinking SMT: Devil Survivor or Tales of Abyss. Until Super Mario 3D Land arrives. Although are there any Virtual Console games worth buying besides Link's Awakening?
Maybe I shouldn't waste my money until Super Mario 3D Land? I love my 3DS... I guess I'll just focus my time now on the DS games I have yet to beat.
Waiting for more info on: LoZ: Skyward Sword, 3DS games, Dragon Quest X, and Wii U
I'll put in a recommendation for Devil Survivor Overclocked. It's great.
A wise man once said, "DODONGO DISLIKES SMOKE"
I'm hoping for Kid Icarus to be my next one. But ah... SM3DL is hardly wasted money.
As for VC games... the Game Boy Donkey Kong game is pretty great. Oh, and Shantae: Risky's Revenge (essentially a DSiWare game).
Read the mania: http://www.fanfiction.net/~nonexistinghero
In SA2, it's Super Sonic and Hyper Shadow.
I love RPGs
If you're willing to play a DS game:
Golden Sun: Dark Dawn
Uncancel Mega Man Legends 3! Join the devroom and sign the ONLY OFFICIAL MML3 PETITION:
http://bitly.com/rigdKs *Please make this your sig*
Buy Samurai Warriors Chronicles.
It's more action than action RPG, but it's probably within your play tolerance.
I will rule the world, and find that truly good cup of coffee.
I'll put another vote in for Donkey Kong for Virtual Console. It has a lot of content for a Gameboy game.
If you're a fan of platformers I doubt Cave Story 3D will disappoint. Although if you've played the original (which is free on the PC) some of the magic might be lost. The game also has some RPG flare, which you may be into. (This comes out in November)
[These next 2 games are DSiware and Technically not 3DS games. I don't know how literal you mean "3DS game" so I'll throw these in]-
For Puzzle games I can't recommend Pictobits enough. I love the aesthetic and overall presentation.
If you're a fan of Tower Defense style games I highly recommend Starship Defense. It's a fun little game that really surprised me.
The DSiware games and DK are relatively cheap diversions with decent replay value, and may be what you're looking for.
Cave Story 3D is a full priced retail game but if the original game is anything to go by, it's an unforgettable little gem, considered a classic by many.
If you like golf games, Let's Golf is a good download for $7. Will keep you busy for a really long time.
Other quality downloads are DK '94 and Link's Awakening.
For retail... I'd wait until Super Mario 3D Land since you already have the best game and since you don't like fighters or Starfox. If you ever see a sale on Steel Diver for $20, then go for it-- fun and unique game, but not worth $40.