Depends on the knife and its intended use, the steel, and the maker. Here's my favorites in the custom arena:
Working knives: D-2, 440V, S30V: Tony and Reese Bose ground finish. You can use them, and they come right back with a scotchbrite wheel.
Collecting only: ATS-34 Hand rubbed to such a fine finish you can't believe it was done by hand: Tom Overeynder, Rick Browne, Gene Shadley, Bill Ruple are all exceptional. But Rick Browne's blades and the entire knife have an incredible mirror finish.
Finest finish on a working steel: Tom Overeynder puts a hand rubbed, almost mirror finish on 440V that rivals most of what I've seen on ATS34. I can actually see my reflection in the one I have.