I don't know why people keep suggesting the 5200 model. I guess its because they are cheap, however the 5200 is utter rubbish! You'll get better performance out of a GeForce 4 card. I would suggest getting a 5600 or up card.
Or even better yet get a Radeon card. Right now they are generally faster and cheaper. I just bought 9600XT myself, and it looks like they have resolved a lot of their driver problems I kept hearing about, because everything for me has been running as smooth a silk. And this is coming from someone who'd swore he'd never get an ATi card.
Newegg.com is great, I recommend it. If you can find cheaper prices for quality, name brand stuff, the service is worth any extra buck you might pay. Generally tho newegg.com has low, low prices.