And now they've sent word that Slife has entered version 1.3, with numerous additions to the interface. The program can now work in the background, and apparently it no longer has to scan your hard drive for all the different applications to track-- if a new app shows up in your usage, it'll start tracking it automatically. They've also added a few social networking options (which sounds like a better idea than an actual feature to me-- do I really want people knowing how much time I spend playing World of Warcraft?) with their Slifeshare service. You can track your friends' activities, even down to what app they're using at the moment.
But while I'm personally not interested in completely sharing my pastimes (I'm sure there's an option to turn it off), I do really like the idea of the program, and I love the abilities it gives you to take a close look at exactly what you do on your computer when. Slife is available as a free trial (will track 3 apps), or as a full application for $34.