Actually, I'm using Xp also, but the first thing I do after I install Xp is turn of that f***ing teletubby theme and go back to classic windows.
<RANT>That XP theme has larger controls, meaning less space left for the really important stuff (such as the source windows when I'm programming)</RANT>
So, if you want to test yourself, go to your desktop properties and change from windows xp theme to windows classic theme, then you can see for your self (Might be a good idea to save your current theme first, so you can restore it later on)
Oh, and since it's Windows Classic, it'll probably be using MS Sans Serif, 8 pts for the text. That's what windows usually uses everywhere else.
Remco