I think the title says it all, and if it doesnt.. Im a huge nerd!
Theres alot of dating sites etc etc, So I would like to list some gaming communities which I visit on a daily basis.
1. ugame
Great layout and easy to navigate. Still in a beta phase but plenty of stuff to do: blog, upload images, make friends, post something in the forums etc..
2. Games
A great site even though I dont get the same 'community feeling' as with ugame. Plenty of news, videos, cheats to check out. Worth a visit
3. FM 09 (swedish) A football manager 09 community, had to mention it though.. because I really like the game 
Articles, Tip, Forums, Quiz etc
4. FZ (another swedish site)
The layout is not the best, but you wont be disappointed anyways. Because theres so much stuff to do. Blog, Read news/articles, watch movies, Competitions (great prices!)
Thats all for now, I hope you like atleast some of the sites 
TC!