@OP: Well, you pretty much have all the good games already. MPH is the only FPS worth mentioning, and there aren't that many RPGs for the DS. FFIII comes to mind, of course, but you already have it. The only moderately scary game is RE, which you also have. As far as Action and Adventure games are concerned, you might want to try Sonic Rush. It's not the best ever, but if you can handle the fact that the game is blazingly fast, you'll like it. Also, if you liked Phoenix Wright, you might want to try Phoenix Wright 2 and/or Touch Detective. Neither is as good as PW1, but they're both pretty nice, and have the same type of wierd dialogue. That's pretty much all I can recommend. Like I said, you currently have all the 'must-have' titles for the DS. Don't expect to find any really good games you haven't played yet at this point. The games I mentioned are nice, but I advice renting them first, because they're kind of hate 'em/love 'em games.

@inzaneetie013: Get AC:WW and New Super Mario Bros. There aren't any good RPGs out for the DS at this time (wait for the FFIV remake), but AC:WW would kind of fill that gap, and has monstrous replay value. New Super Mario Bros. is a shoe-in when looking for platformers. It's got some pretty nice replay value, although it isn't exactly the longest game ever. Sonic Rush is also a pretty good platformer, but like I said, it's very fast-paced, which you'll have to like if you want to enjoy the game.

Pretty good deal.

Btw, should you run into either Tales of Symphonia or Fire Emblem: PoR for a sweet price (~20$ used? They're fairly new.), I'd buy them if I were you. Fire Emblem isn't THAT long if you're good at strategy games, but both are pretty solid games, especially Tales of Symphonia.