Don't get me wrong, I love Bugzilla .. It's free, it's got a ton of features, and it just-plain-works. But MAN, the UI is freakin ugly on that thing. I finally mustered up the stength to quit bitching and starting fixing and I just recently submitted a patch for it:

http://bugzilla.mozilla.org/show_bug.cgi?id=259723 for anyone else who cares about such things and might prefer a different look in their Bugzilla (assuming you're running off the head of the tree)