I just watched a video podcast interview of Joel Spolsky by Robert Scoble. I've been a big fan and avid reader of Joel on Software over the years. We even use Fogbugz for most of our software development process. I think Wildbit has had a licence since 2002.
The interview is long, but offered some insight on the decisions that went into creating the UI and featureset of Fogbugz. For instance, reporting features for managers were left out on purpose. This way developers could concentrate on their tasks and not worry about looking bad by some interpretation of a report. Joel also offered some brilliant insights to what their new version will include.
The most noteworthy feature is about estimations. In Fogbugz 6.0, they will have a feature built in that will track and predict the inflation of a team's estimates. We all know that tasks are never early, and if they are, it's not that significant. In reality, estimates are always late, and in some (most?) cases, very late. This is just the nature of estimating and building custom software.
So what they have built-in is a timeline not based on dates or ideal hours, but estimates and their likelyhood of being accurate (or not). If someone states eight hours for a task, the system will inflate that estimate according to previous history of estimates. At least, this is how I interpreted how it will work. Either way, it is the most realistic way to view timelines for software and I am very interested to see the feature in real use. This reminds me a lot about the concept of team velocity.
I highly recommend watching at least the first 30 minutes of the interview.