I know there is a LOT of information available through simple Google searches and/or searching StackOverflow. I'd be interested in what you found worked for you.
Personally, I've got a pretty strong bias towards simplicity unless I absolutely need a feature. See, e.g., Joel Spolsky's article: "Choices = Headaches"
I found a nice simple bug tracking app that works beautifully to track bugs we're finding in our Hexawise app, but I'd be interested in what you have found works well for you and - equally importantly - what your criteria / value system in selecting a bug tracking tool is. Thanks in advance for sharing your experiences.