Put it this way, if you have 2GB of free RAM, you've bought too GB too much RAM.
RAM should be full constantly.
Of course, older versions of windows had such appallingly laughable memory mismanagement, that when your RAM was full of OS, it STAYED full of OS when you tried to run a program.
XP is a much friendlier customer (I assume vista too), it'll cache vast swathes of itself into RAM and then just re-assign it (as opposed to win98 style, byte by byte moving), as soon as a user process needs it.
We used to get whingers on linux forums a lot "ooooh linux is cack, I only booted and it's used all but 20MB of my 1GB RAM".
Yes, dipstick, and when was the last time you seen that little light winking, the one that says data is coming off a nasty slow hard drive.
Empty RAM is RAM you didn't need to buy, keep chanting it, and it'll sink in.
Of course, if your games are paging their balls off and things are acting downright stroppy, then there may be an issue, but until you see that sort of behaviour, just roll with it.
I'm off to work out how to make a 3GB RAMdisc and load my entire /usr directory onto it at boot.... who ever said penguins can't fly.
