The 3DS has a small variety of RPG's from what I understand, so for now, the most notable ones are:
-Kingdom Hearts: Dream Drop Distance 3D
-Tales of the Abyss
-Shin Megami Tensei: Devil Survivor Overclocked
-Legend of Zelda: Ocarina of Time 3D
-Heroes of Ruin
-Kid Icarus: Uprising
And some DS games, like
-Final Fantasy XI: Sentinels of the Starry Sky
(And all other final fantasy games)
-Pokemon White/Black
(And all other Pokemon games)
So, which one would you recommend and WHY?
(Consider:
Replayability
Gameplays
Graphics
Sound)
I recommend all of the one's you mention except Final Fantasy and KH:3D seeing that I never played a FF game and KH:3D hasn't been released in NA yet. I own and have played all the other titles you mentioned. I have put many hours into Devil Survivor but all the game takes place on the touch screen ( i put 80 hrs into this game and still haven't finished it), Ocarina of Time is pretty self explanatory, Kid Icarus came out to be one amazing game ..not only in solo mode buy in multiplayer ..the graphics, the cheesy comedy, and the music are great, really high re-play ability. Tales is very good too except I found the colors a bit dull as compared to LoZ, and Heroes of Ruin: very short solo mode but very amazing online play with mic chat.
And I would recommend the Final Fantasy games and KH.
Joking aside, you really should play the Final Fantasy series. FFIV for the DS is a pretty good one to get your feet wet with, since we are focusing on the DS.
Also, Kid Icarus is not an RPG. RPGs rely on exploration, story, and setting to tell the story of the game and KI does not really have much exploration at all (not to get into the argument of story). Furthermore, they are characterized by dynamic character interaction, which does not take place in KI either. Oh, and the gameplay mechanics, but that's another variable not worth fully explaining.
Heroes of Ruin would be a good investment only if you have other friends who play RPGs. Speaking of which, Dragon Quest was left off your list of DS games! Dragon Quest IX is the best old school RPG of all time and fantastic to play with (local) friends. In general, if you want an old school RPG, you should grab a DQ game.