New DS.

[OMG SHINY PIDGEY]

So I just got a DS because I wanted to try something new other than the consoles I already own, but I haven't bought any games for it yet because I don't really know much about its library.

Recommend me some worthwhile games? biggrin

I'm not picky about genre. I'll play anything if it's fun, but I do tend to favor action/adventure, platformers, and RPGs.  

[TtheHero]

Kirby Superstar Ultra.

New Super Mario bros.

Those are two good games to try.  

[Skaeryll]

Dragon Quest 5.

Phantom Hourglass  

[Decavolty]

Pokemon D/P/Pl

Anything aforementioned

Anything I've reviewed 8D  

[The Awkwardest Turtle]

Elite Beat Agents  

[l-Kathulu-l]

Chrono Trigger DS  

[Zephyrkitty]

The World Ends With You

The Phoenix Wright games don't fit into any of the genres you mentioned really enjoying, but I feel a need to recommend them regardless.

I'll second the recommendation of Elite Beat Agents and Pokémon Diamond/Pearl, as well.  

[Yin Yun Yang]

l-Kathulu-l

Chrono Trigger DS

Quoted with emphasis.

I love this game.

Also of course the pokemon games, I had fun with the Megaman ZX titles. The first one is a bit harder to get around, but the second one has all the forms of the first and the areas are easier to navigate, though some of the forms you get are pretty much useless.  

[Yumekisses]

Trauma Center: Under the Knife 2

Phoenix Wright Series or Apollo Justice ^_^  

[Prince Noir]

Zephyrkitty

The World Ends With You

The Phoenix Wright games don't fit into any of the genres you mentioned really enjoying, but I feel a need to recommend them regardless.

I'll second the recommendation of Elite Beat Agents and Pokémon Diamond/Pearl, as well.

I second this
but get platinum instead of diamond.....  

[Zephyrkitty]

Anges_Bird

Trauma Center: Under the Knife 2

The first one's pretty good, too.  

[5ir Psycho 5exy]

I enjoyed Phantom Hourglass and The World Ends With You a lot, as new games. Kirby Super Star Ultra and Chrono Trigger DS are absolutely epic remakes, and Super Mario 64 DS, on top of having new playable characters, has a minigame library that will keep you occupied for hours. The Ace Attorney series is addictive and challenging, but has very little replay value simply because of the kind of game it is; I'd suggest renting them if you can beat them fast enough. xd

Pokémon 4th gen is fun. I suggest you opt for the newly-released Platinum if you can find it; apparently it has a lot of updates to the system as well as the storyline to make it run a little more smoothly than Diamond and Pearl.

Star Fox Command, I've only logged a few hours on (it's my brothers' game) but it seems like a lot of fun; it reminds me more of Starfox 64 than some of the more recent SF games.  

[Sharkbutt The Orgiastic]

Yin Yun Yang

I had fun with the Megaman ZX titles. The first one is a bit harder to get around, but the second one has all the forms of the first and the areas are easier to navigate, though some of the forms you get are pretty much useless.

LOL, HAX-ROBO-HORSESHOE CRAB DOES NOTHING BUT FREEZE TIME AND NOT MOVE.  

[Meta_Fish]

Mario Kart DS, Elite Beat Agents, Contact, Kirby Superstar Ultra, Meteos, New Super Mario Bros, Yoshi's Island DS, Sonic Rush  

[misternitsua]

Final Fantasy Tactics A2 was a huge timesink for me. Even though I didn't like the story as much, all the new classes and races really opens up what you can do with your party.

I've heard good things about all of the DS Castlevania games. The one I own is Portrait of Ruin, and it's my favorite of the Castlevanias I've played.

Mario & Luigi: Partners in Time is good if you're looking for a challenging
game.

Even though I tend to go for long periods without playing it, I'd have to say Animal Crossing: Wild World is worth getting if you're into that sort of thing.

Lastly, I have to second New Super Mario Bros. as a definite must-buy.