I run a small Drupal consulting shop and we've been trying different groupware solutions for what seems like ages, yet nothing we've found seems to be a good fit.

• We don't need CRM-overkill such as SugarCRM offers -- it's just too much for our small size.
• We do need git integration (at a minimum, an easy way to associate commits with issues)
• Time tracking on configurable or 15m increments
• per-project issue tracking
• billing (incl. recurring billing for support contracts, etc)
• some sort of per-project notes/wiki for things like login credentials, client contact info, etc.
• Contact logging (Client foo called at 2:20pm and asked to add bar to the spec, signed addendum with pricing due to client NLT CoB today, to be returned by CoB tomorrow)
• Open source solutions are greatly preferred to closed ones
• Most of all, it should be very efficient to use. Several solutions just fell out of use here because they required too many clicks for simple, frequent tasks like logging time spent on an issue or noting a call from a client. It shouldn't take 20 minutes to make a note.

Edit: I almost forgot to mention: we're a mixed Linux/Mac shop with no Windows users.