In descending order of size:
Tony "Mr. 18 Inch" yeah, has erection problems but I've seen it hard
and no one has more dick than this guy
Mandingo amazingly hard for a huge one, funny you never see
him "grow" from soft to hard
Jack Napier huge meaty sausage dick but alas, doesn't get brick
Rambone impressive indeed but one of the femmest acting
straight porn actors I ever saw, lol
John Holmes of course, not a "working" porn stud any more, I
rank him a tad smaller than Rambone
Lexington Steele beautiful huge dick, but not in Mandingo's league
Chad Hunt he's a small guy so it looks huge, but kind of puny
compared to the giants on this list
Haven't had the pleasure of seeing the white guy that nicky9x6 was talking about so can't evaluate him here.