there is no best
If we were talking real world, no there is no "the best" however there are so many different factors in the real world that you just never know. Ex: The Army Special Forces Detatchment Delta (Delta Force) are known, not rumered, but known as never missing a shot in urban combat. They just trains so much that they always hit, it sounds unbeleivable but it's true. Now I have had friends who work as Oposing forces to delta, in training, and they have lived to mess with delta, again in simulations, and they have done this by hiding, sneaking and being smart, one of my friends even came up behind a team and shot two before they could turn around and light him up (however the two he shot were allowed to "live on") So yes the whole group are "the best" shots, however they still got taken down- simple but real world "the best" and they didn't get it done.
Now here we are talking about not only RPG's but Hero, not only Hero but Champions, and comics are loaded with the best. Marvel and DC have tonns of "the best" and so I think that it's possable in champions, even genre nessasary. Heck throughout the late 90's Wolverine's saying was, "I'm the best there is at what I do."
I also agree, what totalls represent "the best" depend on what types of negatives there are in the world being run. And of course depending on the GM.
That's my 2 pennies
-Wolf