What Bug Trackers do you all use?

I have spent the last month looking at different bug trackers, trying to find one that:

  1. Is free, as I want to edit the source code and, quite frankly, cannot see why an apparently simple system should cost so much money.

  2. Doesn’t look absolutely awful (Trac, BugZilla, Mantis, I’m looking at all of you!)

  3. Is easy enough to install on my hosting.

I eventually decided on Redmine, but have spent the best part of this month filling out support tickets because anything RoR doesn’t seem to want to work. I’m at the point now where all I want is a PHP-based bug tracker that doesn’t look terrible. It would be nice if we could also use it as a bug-tracker for external client projects, with the ability for them to log in.

What do you guys use, and if you do use a decent PHP bug tracker can you recommend it to me?

Maybe this will help? Comparison of issue-tracking systems - Wikipedia, the free encyclopedia

I’ve had a quick look through those, but the page appears incomplete and many of the trackers listed barely work or aren’t even out of beta stages yet.