Most amazing gamer you've seen or heard before.

To me, Slayer_Boxer from Starcraft tournaments and Avesta from Final Fantasy XI is most amazing gamers I've ever seen (through videos of course)

Both of these gamers showed me stuff that I didn't think was possible in those games. I don't think even the creators of those games couldn't imagine what they do was possible.

To me, I'd say Daigo. Go watch the bout with him fighting Justin Wong on Street Fighter III: Third Strike. After the ending, you'll see why...Darth_Homer

saw that, but I still think Slayer_Boxer and Avesta is more amazing.

Boxer you should know why he is amazing, and Avesta, she (I heard) defeats monsters alone when the game designers designed it to be beaten with 18 people.

Daigo did something game designer intended for you to do. They didn't design it to be impossible. Avesta did something game designers designed it to be impossible.