I just can't see any reasonable case for evaluating the Sid-ster as the 3rd-best/greatest center of all time.... I think that's kind of bonkers, actually.
As the past few pages of this thread prove, there's considerable disharmony in the notion that he's surpassed players like Mark Messier, Steve Yzerman, or Joe Sakic (I could see the case for that argument, but it's certainly not a clear majority opinion).
More to the point, though: what about Phil Esposito and Jean Béliveau? I just can't see any possible argument that he has bettered them. I mean, what has he done that they haven't done more times?
As I said earlier in the thread, because of the unusual nature of Crosby's career so far (missed games and injuries; very early peak), it's very difficult to evaluate him. He may yet win the Stanley Cup and the Conn Smythe this season or next, and we'll have to re-evaluate. He may play at a very high level, akin to Gordie Howe, until he's 41 years old, and we'll re-evaluate him. On the other hand, if he goes down to another serious injury and is out of hockey within three years with no further major accomplishments/awards (which is certainly possible), then I think you'll see the popular opinion of him decline and his ranking will slightly fall.
At present, the most generous argument, within reason, for Crosby, is that he is the 5th-best center in NHL history.