I've been looking over some available bug-trackers lately ( bugzilla, redmine, trac, mantisbt, fogbugz, jira , chili ) and decided to give bugzilla a try. Why bugzilla? - honestly - all of aforementioned software do good job at tracking bugs and I've simply decided not to procrastinate on this one as often happens when one has too many choices.
Also - I'm not convinced that hosted solution would suit me as I'm the kind of person who likes to be in control of things. I also glossed over chili/redmine purely because I didn't want to bother with ruby stack, although they do beat bugzilla in terms of interface. However - upcoming design change in Bugzilla v. 5.00 does look very very promising: bugzilla design change. IMHO - with bug trackers - I'd just pick one and be done with it.
Bugzilla has been around for ages and is in use by Red Hat, Novell, Mozilla, Apache, Open Office, Yahoo, Siemens, France Telecom and whole bunch of other companies.
Requirements are quite standard for web-app: RDBMS, web-server, scripting language and sendmail compatible MTA. However - IMHO the biggest drawback of bugzilla was the lack of fcgi support ( that was actually the biggest thing that surprised me about Bugzilla ). Basically it's a simple cgi app and that's not changing until version 5.00 at least. Although after thinking a bit about it - this is no biggie, bug trackers are not something that attracts a lot of traffic anyway, so performance would be my last concern.

