Anthony, I’m in the same boat in that I have no interest in loading Vista. I’ll be waiting for Windows 7 before I think about changing operating systems. Until then if you want faster editing then CPU upgrades are going to help more than ram, especially with the ram limit (3.3 gigs I think?)
As for your original question, obviously it depends on what kind of money you’re looking to spend, but nothing helps workflow like more screen real estate. 22″ Acer screens were mentioned and they’re certainly a good bargain, but for my personal taste, I just don’t enjoy having two separate screens unless you’re just using the second one as a monitor. I prefer just having a single 24″ at 1920×1200 so everything can be kept on one display, then an external television as a monitor. That may be overkill unless this is a big birthday, but even one 22″ would be a big step up from that 17″.