Well I have a number of sites that are almost constantly open.
The Escapist obviously, it's where I get most of my gaming news.
ABC.com.au, good mix of international/nation/local news, and unbiased to boot.
Cracked.com, for the funnies.
Spacebattles.com, a forum for geeky stuff.
iGoogle for RSS feeds.
For stuff I visit daily, or at least every other day.
ABC iview, lets me watch stuff that I'm too lazy to watch on TV (Daily Show mainly)
Youtube, Philly D most days, few other subscriptions
Whirlpool.net.au an Australian tech forum
Facebook, usually check it once a night because my friends use it, so helps keeping up.
Ars Technica tech site.
The Register (snarky tech site)
Questionable Content web comic
Penny Arcade! of course
That's about it for the most common sites.