Axosoft OnTime - Voted "Best"
OnTime has been voted "Best Bug Tracking / Project Mgmt" winner 4 years in a row. We'll host it, or you can install it. Scrum-ready. 1 user Free for life ($199 value)!
Get Started In Seconds Totally Free

CounterSoft Gemini - Effective Issue Management
Gemini is a straight-forward .NET based issue management solution that simplifies internal project collaboration and management of End User issues.
Free 5 User License for All!

JIRA.    $10    Forever.
Brilliantly simple, incredibly powerful bug and issue tracking software used by more than 11,500 organizations in over 107 countries.
Free eval or $10 for 10 users forever.

informUp -> Manage your business Up!
informUp is a complete Application Lifecycle Management (ALM) solution. Manages your requirements, tasks, test cases, issues/bugs, and more. Great ROI!
Free for startups. Try informUp now!