Little addons like what spam_can has got are great, but when it comes to speed, there buggers, expecially that glass effect for XP, if thats Windowsblinds then you must be wasting so much performance just for that effect (well even if its different from windows blinds), it's not worth it really. You can get a Vista theme for XP if you really want it, no transparency but it dosen't slow the fuck out of our PC.
Thats my desktop, not that you can see it or anything. Every time my desktop gets full, I select everything, dump it in a folder, and put it in my Documents drive. I have about 4 / 5 folders in there full of crap :\