Yesterday I bought and installed FogBugz to run here at Sampa, a product by FogCreek (you know, the Joel on Software guy).
I was looking for a bug tracking system for a while. FogBugz surprised me because it also tracks Features (although any bug on any system can be flagged as a feature). And they have this even more impressive integration with customer emails.
FogBugz is not a support/ticket system, but it seems to do some of that work. I still need to activate that feature.
The installation wasn't a breeze. It had some issues with my Domain Controller and it didn't give me the option to create a new Virtual Site on IIS (I had to quit the setup, create it and start again).
Once I have a better grip into the product I'll post more.