I don't think it would have to be the fastest, especially if you have a lot of it. I would say just some PC3200 or PC3500, probably made by a good company with a good warranty. I would also try to get it with faster timings. I'm not the greatest with RAM, but I think that would be Corsair, Crucial, Mushkin, Kingston, OCZ, or PQI. I think all of it is good and will work for a server, it's basically personal preference. Someone else might be able to better answer with company or speed. What game(s) are you planning on hosting with this?