>>10
Strange, I use a 3D Desktop and all that fancy stuff is enabled and I still need just 80 MB RAM. XP uses ~200 BTW, and I'm talking right about the "right after installation" part here. The 80 MB are after half a year running it and installing and deinstalling a crapload of programs. Okay, when running Azureus I reach the 300 MB.
So, buying new stuff isn't neccessary to run a modern OS AND do RAM-consuming work. But Windows always had it's memory leaks, so it can't be changed I guess.
And that many ppl use them for video and image stuff is because Macs use this:
http://en.wikipedia.org/wiki/CMYK_color_model