Hi! I'd say that while the Radeon HD 4850 is not a bad card per-say, it is serveral generations old and thus, I'd recommend getting something like a HD 7750, which, for around $10-20 more, performs on average up to 25% faster than the HD4850, while consuming only half the power at peak (110w vs 55w). furthermore, the HD 7750, being a current generation card, gets all of AMD's newest driver and feature updates that frequently improve performance in new games, while the HD4850 has been put on legacy support (no new features or optimizations). Newegg often has rebates on their video cards, which may bring the price down to around $70. Check this out:
http://www.newegg.ca/Product/Product.aspx?Item=N82E16814131481
Good luck on your video card shopping!