Paul Adams - he posts far too rarely but everything he does post gives awesome insight on a level it's rare to find anywhere else.
Shaithis and Kalneil - both argumentative buggers who I'm sometimes with, sometimes against - always entertaining.
Jay is always good for the odd techie nugget to file away sometimes, ditto Dangel.
Hexxeh and TheAnimus are at times like an arguing old couple (in a good way!), and I guess I can throw Aidanjt into that bucket too.
Funkstar is an all round nice guy, Rave is another argumentative sod, Saracen never uses one word when 10 will do.
Everyone, really - the above are just the first few that spring to mind. Thanks all