After years of working with a few free bug tracking apps, we came to the conclusion that they took too long to configure, tended to be too complex for our needs (small web boutique) and too convoluted for non-technical people. So, we wrote our own.
Just launched it as a hosted app. Simple. Efficient. Highly effective. So easy, even clients love it. :-)
There's a free version to check out, and an incredibly inexpensive subscription model.
Would love feedback!