This is a tough one.
RangerBoy I've always relied upon for anything regarding the cap and or contracts. He's always got some sort of proof to back his words up. From time to time he even brings up old facts and things and points out little things that I knew that most on here didn't, and I'm even talking about some of the old-timers who you'd expect to know these things.
Jonathan and I have had many spirited debates over my 7 years on this site. He knows his ****. I've seen him make fools out of many people on other boards who simply resort to flaming him because they can't stand the fact that he knows as much as he does.
Bluenote is one of the best posters I know on these entire boards and as others have mentioned, he has experience and having played at a somewhat competitive level myself, I can tell that he's not blowing smoke out his ass. I may not always agree with him, but there's more than enough merit to anything he says.
I'd say RangerBoy, honestly. To know the CBA and the cap like he does inside and out is just astonishing.
I know my fair amount of hockey and hockey history and I can run off stats off the top of my head, not to toot my own horn or anything, but RangerBoy does take it to another level with the CBA.