Bad Astronomy. Phil Plait is awesome, and also the source of a lot of these links. Go here, read, enjoy!
Dear Astronomer. Nifty blog filled with bunches and bunches of nifty stuff.
The Write Stuff - Orlando based blog all about space. Obvious Florida bias. Which is fine, because also excellent insights.
Astronomy.com. It's a website about astronomy. Did you guess that? Also the website for Astronomy Magazine. Awesome sky atlas.
Astronomers Without Borders - Website dedicated to promoting international companionship via astronomy. Makes sense, we all see the same stars (except people in other latitudes)
Association of Space Explorers - Group comprised only of people who have gone to space. Neat!
Planetquest - Directory of all known exoplanets
SpaceHack - Citizen science projects having to do with space/high atmospheric research. Rockets are sometimes involved, which is awesome.
Parabolic Arc - News and Editorial. Big on space tourism.
Colorado Space Grant Consortium - State run program aimed at getting Colorado students access to space. (Grants, projects, funding, etc.)
NASA mission Kepler - Homepage
NASA Watch - Critical reviews of NASA
Roskosmos - Russian Space Agency
Canadian Space Agency - Canadarm kicks ass
International Space Exploration Coordination Group - Group dedicated to creating a coordinated international plan for space exploration. So only modest goals allowed I guess.
Commercial Spaceflight - Web site dedicated to commercial space flight. Duh.
Space Commerce - NASA Watch derivative focusing on commercial space.
Colorado Space Coalition - Collection of aerospace companies in Colorado, making Colorado a pioneer aerospace location.
P.S. I was originally going to do a one off post, but than I realized I have a lot of links. So I'll be posting more as I get them organized. I would also note that I do not use these links everyday. Most are resources, data archives, and things of that nature. I visit them on an as needed basis. Bad Astronomy is a daily habit though.