Software :: Any Project Time Tracking Application Out There?

I'm looking for recommendations for some project time-tracking software. I have given Studiometry a go, and it looks quite fully-featured (I like the integrated invoice generation and timers), but would like to solicit opinions on other options. Studiometry seems to include everything I need, plus a bunch of stuff I don't. Also, stability questions arise -- this app looks huge and complicated (from a code standpoint), and seems to have a few stability issues. In addition, the interface isn't very "Mac-like," which is something important to me (hey, an ugly and counter-intuitive application is horrid to use, even if the code is rock-solid!).

For those freelancers/project managers out there, what time-tracking and project management software do you use, and what are your likes and dislikes? I'm looking for recommendations for software that can maintain a list of clients with a number of projects under each client as well as individual timers for each project. Studiometry allows multi-user situations, which is a boon, but not required, since I have more than myself working on any project at a given time. I can search versiontracker.com myself, but before I go downloading and trying 10 applications, I'd like to hear some opinions from real-world usage.