RescueTime is awesome, one of my favorite tools. Not only because it tracks my time working, but just knowing it's own makes me less likely to waste time online - because I know at the end of the week I'm going to get an email saying "Hey Sid, we know you spent 8 hours in front of Google Readers." My first week I think I spent 1 or 2 hours in RescueTime (tagged "navel gazing") but part of it was useful, I was tagging stuff!
The news filter feature is killer. I'm going to set that up this weekend.