IE6, IE7, FF...

Using these stupid hacks is discouraged by some people smarter than me. However, should the need rise, here's a hint from some dude Neil Kilbride:

"Although Firefox and IE7 and more similar than ever in rendering CSS, IE6 has always had a mind of its own, adding padding and spacing amongst other things in random locations. However, there is a simple way to cater specifically for the major browsers. IE6 recognises underscore lines, but IE7 does not. IE6 and IE7 recognise period lines. For example..." (link to complete post above).