I just setup osTicket yesterday, and this system is absolutely fantastic. I've been a user of OTRS, and that system is just way too complicated for 95% users out there. While OTRS took me a couple days to setup, it took me less than half an hour to get most of my osTicket setup done. Great job guys!
Anyway, I've been playing around with it, and I thought it'd be nice to have an expected completion date field or a progress bar so clients would know the status of their help request. This way they don't send millions of "please dont forget about my helpticket" e-mails kinda thing.