the previously posted board has sata so get a sata hard disk not an ide, the speed incerease is noticable, especially when loading games like half-life2.
graphics wise there's an ATI sapphire X1600 256mb out fairly recently that looks good, get the xt version if you can afford or or even look to the X1800 series or nvidia 6800 series
http://www.microdirect.co.uk/ProductInfo.aspx?ProductID=10165&GroupID=1091
i know it's a UK site but i think this is a good board if you have a graphics card already that's agp and want to hold off upgrading, although not really relevant to you because you need a new graphics card
bonuses of that board:
sata-2, 300mbps if you get a sata-2 hard disk, more than double ide speeds and potentially double sata-1
pci-e x16 and agp if you want to stick an older card in for some reason eg there's a problem and you want to test if it's the graphics card.
has 7.1 onboard surround sound
up to 4GB ddr400
supports dual core
has an expansion slot for their 940 socket expander so if you ever want an opteron you just need to buy a small card that slots in instead of a whole new motherboard