Digg - I love this site, I go here many times every day. "News stories and websites are submitted by users, and then promoted to the front page through a user-based ranking system." (Description from Wikipedia)
Diggnation - Going along with Digg, Diggnation is a podcast that covers some of the hottest stories from Digg.com each week.
Demonoid - Great site for downloading whatever, although it's down at time of typing. Invite-only.
TorrentFreak - Provides information on torrents and the like.
GameFAQs - This is my homepage. Video game FAQs, codes, message boards, poll of the day, etc.
Wikipedia - Everyone knows what Wikipedia is... I can search for one thing here and wind up spending a ton of time looking at other articles.
XKCD - Just recently became interested in this site. It's a great webcomic, I highly recommend it.
Lifehacker - Blog providing life hacks and tips for Windows, Mac, and Linux.
GBAtemp - "The largest GBA and DS community on the web."
TwoKinds - Great manga-style webcomic, still in progress.
QJ - Provides a lot of video game information. I use it mostly for the PSP section, as it covers many homebrew stories.
Youtube - Who doesn't use Youtube? I use it a lot for watching video game reviews and the like, as well as AMVs.
Google - I, like many others, use Google almost every day. It's a valuable asset, and the name has become synonymous with searching information on the internet. Not to mention they offer the best email service on the internet, Gmail.