Some of you Windows XP users may use or have used StyleXP to skin your desktop with XP themes. StyleXP uses Microsoft's native skinning (or theming) engine, so it doesn't slow your system down like WindowBlinds does. I took it for a trial run (it's available as a30-day free trial) and it was cool to see how pretty it can get - Luna Blue is really, really tacky and I hate Luna's guts. I'd rather use the "Classic" style and I do in it first thing in a new Windows XP system. StyleXP allows you to use custom themes (or rather, Visual Styles, as Microsoft calls them) like those from customize.org and ThemeXP.
But I didn't like to have to pay for something that really should have been in Windows XP itself. It turns out, there exist ways to patch Windows XP such that you can use these custom-made themes. The easiest way is using PatchXP - I've tried it and it works on my Windows XP Professional Edition with SP1. Another way, which is slightly more of a hassle, is via Multi-Patcher - this is more likely to work, since it's more updated than PatchXP. Have fun. This should tide you over until you make enough money to get a Mac, or have enough energy to customize KDE to the max.