if you are using your computer for home stuff, like gaming, burning CDs, internet stuff, go with pro. server uses up a LOT more resources by running a lot more stuff in the background. only use server (or adv. server) if you are actually going to use it as a DHCP or DNS server on a home network, and even then, it's kinda overkill. i had it as my main OS for a while (back when i had 128 megs of ram) cuz i'm going for my MCSE and it made a good learning tool, and it was crazy slow. i have quite a bit more ram now, but i'd rather be using it for applications i'm using than background stuff i'll never use.