Allnetic Time Tracker allows you to break down time into projects, tasks and subtasks, and then rolls up the time into totals.

I’ve been using TraxTime for years. My only beef was that there was no way to effectively separate billable time from non-billable time and still keep accurate running totals. But it has a totally butt-simple interface.

Updates 10/7/2005
TraxTime is now in version 4.x and now can deal with billable and non-billable time, at the time segment level. For example, if you put in 1 hour for a project, and then enter a second hour, but only want to bill for one hour, you can flag one of the entries as non-billable. This was the main reason for me looking elsewhere for a time tracking program. Upgrade cost from version 3.x to 4.x is $20.00.

Allnetic has crashed repeatedly on my Windows XP machine. I don’t know if it is conflicting with other desktop programs (like Konfabulator). I received a note back from their tech support, saying they know about the problems and are working on it.