Bug tracking SaaS

[Paul Makepeace]

Any recommendations for online bug tracking tools? We've tried
Lighthouse but it's a little too basic: no facility to make issues
dependent on others; no way to multiply assign (not sure if any allow
this actually); all issues lumped under a single project; etc.

We don't just use it for bugs but the complete cycle of a change
request so for example opening a ticket to implement a feature,
discuss, implement, code review, and push thru' testing, stage, and
live.

Or, is bugzilla or whatever that easy to set up that I should JFDI?

Thanks,
Paul