I'm a big Sims fan and I would reccomend these:

New Super Mario Bros.
Pokemon Diamond/Pearl
Animal Crossing: Wild World
Nintendogs
SimCity DS
Brain Age
Brain Age 2
Super Mario 64 DS
Clubhouse Games
Yoshi's Island DS
Kirby: Squeak Squad
Planet Puzzle League
Picross DS
Crosswords DS
Electroplankton
Tetris DS
Mario Kart DS

Heh...

If she likes mystery games, I heard Hotel Dusk: Room 215 and Professor Layton and the Mysterious Village are good, but I haven't tried them myself.

get viva pinata when that comes out

i think she would like professor layton, nintendogs,animal crossing, hotel dusk,trace memory, plus there are some sim games on the ds

Mario Kart DS
New Super Mario Bros.
Prof Layton
Hotel Dusk
Nintendogs
Animal Crossing

its all good.

The Sims for DS isn't The Sims.

DO NOT GET IT

Animal Crossing is much better than Sims on DS.

I got Yoshi's Island DS for my girlfriend and she loved it. You can also try Kirby: Canvas Curse (played with stylus only) although it seems to be out of print... I found it used, didn't play much yet though.

Don't forget to post a pic with her playing in underwear as a thanks for the people who helped you pick games.

Mario kart DS :)

Mario Kart DS, New Super Mario Bros., Meteos.