IMHO don't mess around 9800 pro is the weapon of choice. It can be picked up for as cheap as £130 (well a few weeks ago) you won't need to replace it for years. Can cope with anything you'll throw at it.
I wouldn't be so sure, I managed to get a Radeon 9800 Pro for about the £130 mark and after a week of installing, reinstalling buying a new power supply and various other attempts including running through a 5 page file from Ati my computer still crashed all the time. Whether this is somehow due to the card needing its own power supply as well as the power it gets through the AGP slot, or whether there is a faulty component on the graphics card I don't know. Its true the 9800 is, if not the best certainly at the very top but looking back now I wouldn't buy one at £130 again, I'd spend the extra and get a branded card at about £70 extra. Perhaps its just because I've had so much trouble with mine that I don't like them. Anyway I've bought but not received yet a GeForce 5900 XT by MSI for about the £150 mark. Not as good a card as the Radeon I had perhaps but hopefully this'll work.
buying graphics card from a major reputable maker is a must in this modern era of razor-thin margins for IT products.
because of the thin margins, there is always the possibility of cutting corners by some unscrupulous makers. small, unknown, or new comers in this hugely dynamic market of graphics cards may not (have to) treasure the quality factor as much as the established players.
i don't agree that graphcis card replacement has to be a yearly affair if some reasonable foresight is employed in the decision-making process.
get a 256MB Radeon 9600 XT made by a major vendor with proven quality performance and cs supports, and you should be worry-free for a long time to come.
by the way, you might want to take a look at this recent thread of same topic click here.