In reply to waterbaby:
When I first log on - email, Facebook, Google Reader to catch up on (a) webcomics (b) scientific papers (c) a few important blogs.
Lunch break or other "down time" - UKC, other forums, Reader for the rest of the blogs I'm subscribed to.
That said, since I work at a computer, if I'm involved in a conversation here then I'll check far more frequently than once a day.