Busiek was my favorite. I kinda liked Bendis' run in parts and Hickman's was obviously fantastic. I guess you could say that Hickman's run encompassed a lot more of the Marvel Universe than just the Avengers but seeing as Iron Man and Captain America were probably the two most important characters, I still view it as a seminal Avengers run in the end. "One was life, one was death".
And "The Ultimates" of course.