There are some really great sites out there these days. Hard to pick "the best" one though. What are the criteria?
I like to think we've got one of the best "mega" sites out there with chisel.com just due to it being around along time, having good name brand recognition, 10 years of in house shot content, all the good plugins and live chats, etc. Our conversions are consistantly under 1:100 and our retention is great.

I'm sure there are quite a few out there that can boast the same though, like badpuppy.com, nakedsword.com, bearmagazine.com, etc.

Dave