Really? All 4 of the machines I have at home have <= 256MB of RAM.

Ah, but you'd be surprised how much faster a machine with 256MB of RAM is when you add just 128MB more. I'm talking Windows here by the way.

By the time you have installed a bunch of crap on it your average Win2k/WinXP machine it has used about 260MB of memory by the time it has booted and opened a couple of apps. Having a bit of memory spare by the time you get to this point really helps and makes the machine feel much faster than you might imagine.