Thabeet is a "great" college center? The center position must officially be dead.
To answer the question, Oden by far. Hibbert and Hawes will be the next two picked I think, and I also think they will be close in terms of pros. Thabeet could be up there, but there is no predicting what he will be. I think Aaron Gray will go first round and could be a steal, and NBAdraft.net has Jason Smith in the 1st round.
And to clear things up, I don't think Noah, Glen Davis, Fazekas, and guys like that will be NBA centers.
Glen Davis belongs NOWHERE near this conversation. His game will not translate to the NBA, although he had a solid Collegiete career. Thabeet willl be nothing more then a weakside shot blocker if he declares this season, so it's all down to Roy Hibbert and Greg Oden. It's not that big of a difference between these two in my opinion, so it all values on which of these big men's game's translate better into the NBA, which I think will be none's enough for them to be as great as expected, at least in Greg's case. Oden will be the better pro though.
If Glen Davis can make more strides in improving his body like he did from his sophomore to junior year, he can play in the NBA. How much is there that Sean May does that Glen Davis can't do? Or Udonis Haslem, who was a chunky kid at Florida who transformed his body?