I've played fantasy sports consistently over the last ten years on the larger sports sites, but have found it was mildly competitive and always their secondary purpose (at best). When I stumbled upon ProFSL, I was blown away with the organization of the site as well as the progressive thinking. It is very interactive and well laid out. The variety of sports is second to none. The community is competitive but friendly....I've actually made some "friends" in this league, and it almost feels like a fraternity/brotherhood (and our few ladies who are awesome as well). I can't imagine someone who loves fantasy sports NOT being a part of this website and it's leagues.
Now, if only I can figure out how to make this my career!