My top three are certainly:

Cutmemick, Wacko and Bilbo, they all contribute a lot to the forum and I always enjoy reading their posts. Mick's knowledge of things worldwide is good, and Wack's RBR's and breadth of knowledge across the divisions is impressive.

And Bilbo's sense of humour works really well on my level so I gotta say that dude makes me laugh till I have a brown-pants moment.