Atlassian has released JIRA 3.1, a $1200-$4800 payware J2EE-based bug
tracking and project management server application. Version 3.1 adds
customizable CSV import and improves the SOAP and XML-RPC remote interface.
I've been using Jira lately with Jaxen and Apache.
It's a definite improvement over Bugzilla. I'm not sure it reallly does anything
that Bugzilla doesn't do (at least not anything I use) but the user interface is about a hundred times cleaner.