I need handheld advice...

My 10-year-old daughter has asked for a portable game system for her birthday, and my ignorance in that area is considerable, so I'm looking for some advice.

I looked at the new Sony PSP. It's beautiful, but I think $250+ is way out of the price range, and, being new, there aren't many games for it.

So, what should I consider? She's probably going to be renting most of the games (at least initially). In the PC, she spends most of her time on games like zoo tycoon, though she has wider-ranging preferences on the XBox (anything from Fusion Frenzy to driving games to a bit of co-op Halo with her father...)