First, get Animal Crossing. If you've played it on Gamecube, you know it's awesome, and unlike any other game. However, the DS version is much better. Make sure you have online though, for the best experience.
Metroid hunters, animal crossing, final fantasy 3 and diddy kong raceing is good just not as good as the 64 one, and if you like pokemon diamond/pearl come out aprill 22nd
Advance Wars seemed cool for the short time that I had it. I loved how you could play multiplayer by passing the DS. But once I finally had a chance to play multiplayer, while my friends and I were waiting at a resturaunt, they wouldn't do it. I guess being seen playing a handheld at a resturaunt isn't "cool" to my friends. I was so disheartened, I never played the game much again.