I didnt mean to turn down the DS idea. I just wanted you choose appropriate games for her.
Games like Build a Bear work shop, Crayola treasure adventures should be playable for a 5 year old. I know lot of kids in that age having DS. Just that I don't know the games that are suitable for them. That is why i suggested you to check game sites for games that are appropriate for that age group.
Store employees will sell games that have the highest margin, do your home work before buying games. Every game console has a equal amount of good and very bad games. Just be wise to check reviews, collect some info before spending 30$ on a game.
My 5 and 1/2 year old daughter plays with a DS lite daily. they are tough little systems and now have Smart girl/boy games which are educational and fun for this age I would recomend getting one but stay away from some of the more intense games.
I can not suggest the nurf armor enough for the little crowd. It really protects the DS. I have found that the DS is easier for my boys to do than the games that you hold the controller & have to watch the TV to play. Some games that you may want to look at are .. Animal Genius (the leapster has a version of this game), smart kids, smart boys/girls, Crayola Treasure Adventures, Disney Princess: Magical Jewels, Go Diago Go, Strawberry Shortcake: Strawberryland Games, Dora the Explorer: Dora Saves the Mermaids, and I Spy Funhouse.
Your child really needs to be able to hold a very small stylus, gently tap or move it around, and be able to read some basic commands. Nintendo is putting out some great DS games for younger kids and it's certainly a better choice in the small handhelds than a Sony PSP which I think is geared towards teens and adults. My daughter is now almost 11 and she's had a DS since she was 7. I think it certainly depends upon your child, but for mine, 7 was the perfect age.
Instead you may want to consider a Leapster handheld unless he or she already has one? They have great games and are similar in size.
It depends on the kid and it depends on the game, but when I was 5 1/2 I was playing a regular Nintendo console perfectly fine--and kids these days tend to adapt to computers and electronics even more quickly than when I was a kid. Just pay attention to the ESRB ratings and you should be fine. These systems are pretty durable, though you'll want to keep your eyes open to make sure she doesn't keep leaving it on and laying it down somewhere and running the battery down, and you might want to buy some extra stylus packs in case she loses the two it comes with (they're pretty small, and not attached to the system in any way).