i just purchased 2G of OCZ RAM to upgrade from 1G of Corsair.
OMG, it's like i have a brand new comp. I generally have at least 2 browser windows open when i game, and the ability to switch apps without noticeable lag is night and day between 1G and 2G of RAM. Regardless of what the recommended hardware is for newer games, 2G of RAM is a necessity, imo. I seriously can't believe how much of a difference it made.