Ask HN: Recommendations for a light-weight issue tracking system

We are starting off with a new consumer oriented web service. It's a small team (less than 10 people). And we need your help with recommendations for a issue tracking system (for bugs and features).

I believe we might not need all the features of a traditional issue tracking system like bugzilla or JIRA. I've used trak in the past, and found it pretty light weight and easy to use to create new issues/milestones.

Do you have any other recommendations? Perhaps even a tracking system as a service (hosted).