Yep, that's what I got. Right now, my DSLite is doubleteaming Castlevania: Portrait of Ruin for DS and Castlevania: Aria of Sorrow for GBA. Another game you guys need to get is The World Ends With You, probably the best game on the DS imo. I couldn't put that shit down at all, I played all the way through (a good 10 hours or more of story play) in about 3 days.

There's also Professor Layton and The Curious Village that's great for those that like puzzle games with a sequel coming out at the end of the month. It's got a very enjoyable storyline, kinda kidish, but the puzzle games in it are definitely top notch. A similar game to this is Hotel Dusk: Room 215 which is more like a mystery novel than a puzzle game. It still has it's puzzle like theme where you play as a detective trying to understand everything that's going on in this hotel.

The Pokemon games are always good, I have Diamond and Platinum and almost played through both. (at Elite 4 on Platinum) They're also remaking Gold and Silver for the DS as well, dunno if I'll buy one, but that's still pretty awesome.

You got Chrono Trigger on the DS also, another game I couldn't put down once I started. I have all the Trigger games now on each system it's been released on, SNES, PS, and DS, and it's never gotten old. The DS version also has some added zone after you beat the game, I haven't got to it yet, still trying to get all the endings.

I didn't play the FFT game on DS, but my friend has it and said it was decent, but there's also the remade versions of FF III and FF IV which kick some ass.

My brother got me Ninja Gaiden Dragon Sword a year ago and I found it to be pretty entertaining. It's pretty short, but it has a unique combat style that I liked a lot. It's the only NG game I've played, however, so I don't know where it stands with other ones.

Lastly, I just got Castlevania: Portrait of Ruin, and once again, I couldn't stop playing it. If you've played any of the other games in the series, you'll find this one to be just as good and then some. Has real good replay value and the two character combat was a great addition that I enjoyed. There's two other Castlevania games on DS, Dawn of Sorrow (sequel to Aria of Sorrow) and Order of Ecclesia. Now that I've played PoR, I'm really interested in playing the other two as well.

These are all the games I can think of off the top of my head, I know there's a shit ton more out there that are just as good. The PSP might have the graphics and such, but DS obviously wins in game enjoyment.