Hi Steve,
I like RescueTime, but I generally use an Outlook Add-in called
Qlockwork to track all my PC activity, and I find that browsing accounts for less that half my time wasting - the worst time wasting I do is email related. I spend way too much time reading emails rather than actually acting. It helped massively to turn off all email notifications; sometimes I spend a day with my email cut off and tell my team to phone me if there's a crisis. That's rather effective, particularly as I find that a session of web browsing is often initially triggered by an email.
Anne.