You need DDR (not DDR2) ram for that board. What kit you go for depends on your budget. You're best looking to get a 1gb (2x512mb) or 2gb (2x1gb) kit so you can run the memory in dual channel mode. Anything by Corsair, G.Skill, OCZ, Patriot and Geil will be of good quality and comes with a lifetime warranty. For the A64 platform, timings are important, lower = better. Might be better looking for a second hand kit also as memory prices are very high atm.