Crosby=Center. Ovechkin=Wing. Centers are always more valuable to a team than wings. They also are better pieces to build teams around.
I don't know how you concluded this, but that's ridiculous. Ovvy and Cros both are elite players and it's pretty hard to say one is "better" than the other (i prefer Ovechkin). Ovechkin brings a physical presence and an unmatched knack for scoring, whereas Crosby is an excellent playmaker and seems to be a natural leader. Ovechkin's physicality could catch up with him though (see Peter Forsberg).