I managed to fix what was wrong with the Blogsnob ad this morning. It's still acting a little funny, but now I know why (even though at the moment I'm too lazy to tweak it some more). The background appears odd when comparing a regular monitor with an LCD, but then again, both of them always render things differently.
It looks okay on Windows 2000 and Windows XP; I'll probably test a Mac tomorrow. I want to see how it looks on Linux, but I don't know anybody who has access to one. As for browsers, it's fine on MSIE 5, MSIE 6, Netscape 7, Opera 7, and Mozilla Firebird 0.6; however, it looks like crap on Netscape 4.8 (I hope nobody's still using that one except to run particular applications--in my case, a biomolecular imaging program). I suspect this won't look good on other older browsers either, but most people aren't using them anyway.