For internal development team I'm looking for a bug tracker.
Important requirements are:
- Free (must have)
- WAR/EAR-deployable (must have; support team prefers to have all apps deployed same way)
- Nice UI (nice to have)
UPDATE
Since I wrote this, Atlassian has introduced a $10 (ten, not ten thousand!) version of JIRA for 10 developers. I think it's as good as it can get -- best issue tracker out there with all enterprise features, for the cost of a few coffees. I have bought it for my current group out of my own pocket (to avoid bureaucracy).