for the most part the only games worth getting for ds are first party games or anything made by square enix
The World Ends With You was awesome, IMO. (I don't know why some people bash it...it's not too hard, and the difficulty is very customizeable, so I was always challenged. You just have to sit through the stupid opening clip that first time where Neku is all emo.) I'd also recommend Disgaea and Chronotrigger. There are plenty of others, too.
You got some good games! I personally really liked the LoZ: Phantom Hourglass and Dual Strike is really fun too (hell, all Advance War games are good).
I love New Super Mario Bros. and Kirby Super Star Ultra. In my list of top ten platformers. I also love Metroid Prime Hunters.
Not one mention of Elite Beat Agents or Metroid Prime Hunters or Sonic Rush or the Ace Attorney games (Phoenix Wright and Apollo Justice)? For shame. Those games are friggin' stellar.
Oh yeah, forgot about Metroid Prime Hunters, one of my favorite 3D shooters on the DS. Adding to list now... EDIT: 1000th POST!!!!!! PARTY TIME!
RPG/Strategy only: Chrono Trigger any and all FIRE EMBLEM (Thank god someone gave it credit) Any and all AW, my fav being duel strike the Mario and Luigi rpgs For people who want the best game, heres what you do. GO BUY GTA:CW OR I MIGHT HAVE TO BEAT YOU WITH A 2 FT. RUSTY IRON POLE. AAHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH. Ahem. Sorry bout that. But really, I've gotten roughly 10 hours of game play, and my completion % is exactly 40.26%. So really, go get it NOW!!!