I use Google's Reader a lot to keep up to date, as best I can, with papers, blogs etc. I was interested to see the 'power users' post recently about what certain influential people read.
No great surprises, and I would have liked to see what people in more scientific fields are reading.
I would guess pharyngula, Bad Astronomy and a smattering of Nature, Science type things.
I didn't see XKCD on any of their lists, shame.