Phoenix
Pretty site of the day: the Phoenix Help pages at Texturizer, though the particular page linked here uses a table rather than pure CSS
I played with Phoenix at work today. The last time I tried it, back in version 0.1, I wasn’t impressed. Now it’s up to version 0.5, and it’s very nice when you add the Preferences Toolbar and a theme. It almost makes Windows livable.
I also found the guy who did the old style-switching Mozilla page that partly inspired my own style-switching efforts.