I don't want a fancy bug tracking suite. Sometimes I am working on projects/tools for myself, and I just want to keep track of any bugs, features, etc.. as I go along. I keep these in TODO and a bugs.txt for now, but it would be nice if there was a typical bug tracking system that would be stored with the project or solution file itself.
EDIT: To clarify, if I have to run any server portion to access it (website, database, etc..) then it becomes sort of useless to me. I want it stored with the project itself so that I can open it up on multiple computers.
Another free for single user product is Axosoft's OnTime. It has a Windows client, as well as integrating with Visual Studio. Uses MS SQL Server as store, and supports SQL EXpress, so it's still free.