Cooper and Bassett were the two best I've seen, but I've only been following since 2001.
If we're solely talking talent, I'd take these two, plus Jeremy Fears. I give credit to Simmons and Geno Ford for getting the most out of their talent, but they aren't as good as Cooper, Bassett, or Fears in terms of talent - in my opinion.
I go back to 1995 for my OU hoops knowledge, so I know there are others from 1968-1994 that should fall in this list.