All great choices. When it come down to great pure wrestling ability, I would say that some of the best names that come to mind would be...
Couture
Coleman
Lindland
Randleman
Severn
Kerr
Hughes
Sherk
When it comes to bjj, judo and other sub guys...
Nogueira
Shamrock
Sakuraba
Sperry
Gracies (take your pick)
Parisyan
Penn
Rodriguez (before he went down hill)
In my opinion, Fedor falls more in the middle. He can grapple, pound and sub just about anyone. But maybe I am a little biased there.
There are a lot of other great grapplers and submission fighters out there. These are just the ones that popped into my head at the moment.