Sure, I have heard about font-smoothing and how not having it, really screws up your rendering. But hearing it and seeing it on your own xp installation is a different thing. I just saw this on my machine and I just had to share it with you.
Safari on OS-X has the best rendering in my opinion

Rendering the default font, instead of just showing white is better in Firefox 3.5

Even IE 7 does quite a decent job.

As allways, IE 6 screws up bigtime

But hey, screw IE6 I say. Not really, just go and check out this possible solution. I am just now testing it and would like to know what you use or prefer..