OK, so now the site should look about the same with IE (6 and 7) as it does with Firefox and some other browsers I've tested. Some hover-effects don't work, but this shouldn't affect the sites usability much.

Most bugs I was already familiar with, but one was new to me: the negative margin bug. You can run into it even if you don't use negative margins, but the fix is the same: Specifying three rules (that shouldn't do anything) on the buggy element:

position: relative;
zoom: 1;
margin-top: 0;


Note that "margin-top: 0;" is not part of the fix in the above mentioned article, but fixes alignment at some places (actually moving the element down, not up, as one might expect).

More handy info on CSS bugs can be found at Position Is Everything and hasLayout.