if you want to upgrade your graphics
look for one with a pci x16 2.0 slot, thats the newer slots
for your sound, look for one with 8 channel sound
or a open pci slot, so you can put a sound card in it, all motherboreds come with sound installed on them
also look at how much ram it can hold, i would find one with 4 gigs being the very least, what cpu socket it takes, 775 and 1333 are new for intel, and am2 and am2+ are good for AMD systems,