Random responses:

1) Bug tracking systems are almost universally loathed by engineers and I think it's only partly due to poor design/interface. I think it's also partly due to the fact that bug systems are effectively criticism. YOUR STUFF DOESN'T WORK. It should be constructive criticism, but some times it's not... I have seen more heated battles in bugs than I have in conference rooms.

2) I'm a fan of intergrating bug tracking and version control. I like to be able to draw a correlation between a bug, a check-in, and a build. That is a good thing. No company I've worked for has successfully done this and I generally avoid initiatives which involve combining bug tracking with ANYTHING ELSE whether it's version control, testing, tasks, and/or features. (more below)

3) Bugzilla is a nightmare to use. Huge proponent of web interfaces here, but I need a robust front end to manage bugs... I need to be able to sort by columns and I don't want to round trip to a damned web server to do this.

4) A problem with really successful bug tracking system is that the company starts tracking everything in it and then you end up with a system cluttered with bugs, features, tasks, whatever... I'm a database guy and I want to see everything in a database because it gives me a warm fuzz, but overloading bug tracking systems means more work for everyone and a poor signal to noise ratio.