I'm interested in building or buying a task-specific computer for my brother. His requirements are ridiculously simple: the machine has to be able to wait in hundreds of web-based virtual waiting rooms at once and not crash. To be competitive, he needs to be able to enter the waiting rooms an dauto-refresh them faster. My question is, what priority do I give the different specs? My initial surmise is this:

1. Connection speed (nothing to do with my build, but I kind of think this will be more beneficial than anything I build for him)
2. Memory size -- I don't usually see firefox taking up more than a gig, even when heavily tabbed, but I think one gig for the operating system and two gigs for the browser are necessary.
3. Processor speed -- I think the processor will affect performance, but even something out of date will do what he needs
4. Memory speed/RAM bus -- I doubt this will matter much, but it seems just on this side of irrelevant.

Everything else is a non-issue for him. Does this seem to stack up correctly?

Also, since he's looking to stay on the cheaper side, and I might end up recommending a refurb to him, is there anything particularly egregious that Vista would do if it came pre-installed? If I build it myself, I'll give him linux, but if I have it shipped to him, I'm not sure I could walk him through the install process for linux, but I probably could walk him through the process to upgrade to Windows 7, if it were somehow worth it.