My 6 year old cousin likes New Super Mario Bros.
I'm sure she also likes Super Princess Peach.
And I know when I was little, I grew up with Tetris.
But if possible, try and give her a few RPG's as text-hheavy they will be.
They will improve her reading and possibly her vocabulary.
Wizard of Oz.
Kingdom Hearts.
Mario and Luigi 3
Scribblenauts
Pinky Street Kira Kira Pop Princess
Pinky Street Kira Kira Pop Town
Animal Crossing
Clubhouse Games
Elebits The Adventures Of Kai And Zero
Pokemon
Final Fantasy Crystal Chronicles Rings of Fate
Elite Beat Agents
Kirby Canvas Curse
Mario Kart
Mario Party DS
Neves
Any Language Coach - Personally I pick Japanese so she'll have better luck with future games.
Peggle Dual Shot
Rhythm Heaven
Summon Night Twin Age
Legend of Zelda, both of them.
Super Monkey Ball Touch and Roll
WarioWare Touched!
Super Mario 64 DS
Sally's Salon
Now I have more "recommended" games for any age, but I really think these are the funnest a 5 year old would be able to play.
And they're not just for fun either, some of them are subliminally teaching ones. The ones in bold are absolute musts for a 5 year old, but if possible, try and include all of them.