Arvidas, Smits, and Laimbeer deserve to be on the list, but are a little high.
Hakeem/Shaq has been debated before - a lot during Nick's Historical Draft. I think Hakeem was the overall better center, but looking at past youtube clips of Shaq, no one but no one could stop him - even Wilt.
Shaq in his heyday was just too strong. Hakeem played him extremely well, but still could not outmuscle the man.
And Dwight? Well, I think he doesn't move too far from where he's at, even with the switching around. He needs to develop some offensive moves.
I'm just glad we have both JO and Shaq now - they both have played well VS Dwight in the past. DH appeared to be getting better in last season's playoff series, even though Perk did a fine job on him.
And who did Dwight have tutoring him this off-season? None other than Hakeem:
http://www.chicagotribune.com/topic/os-diaz-dwight-howard-0803-20100802,0,5776259.columnThis may or may not mean a lot, though. DH had Patrick Ewing tutoring him, but did not seem to get much better.
If he listens to Hakeem - DH may be a huge load this season.