ClearType:
I just had my Windows configuration reset, and I noticed how clunky many of the displayed fonts looked -- darker, bulkier, and generally less pleasant to look at than before.
Then I remembered that I had ClearType set, and needed to reset it. Fortunately, our invaluable tech support people were able to remind me how to do it: Right-click on the desktop, and then click on Properties / Appearance / Effects / Smooth Edges / ClearType. (At least that's how it's done on my Windows XP office system.)
With ClearType on, things look much nicer than with the default setting. I'm sure it's not for everyone -- the results may vary with screen size, operating system, and of course your personal aesthetic preference -- but I suggest you check it out.