When it's all been said and done.

[JoeRedskin]

Also, something from a more historic perspective, and based on GTripp's comments about Brady as a system QB -

In some respects there seems to be a progression of the "Really Good/Great QB Meets Innovative System" behind the much of the Best Ever debate.

Luckman/T-Formation; Otto Graham/Paul Brown's Innovations; Montana/West Coast Offense; Brady/Spread Offense.

These QB's seem to follow naturally from the former and become innovator's in their own right. Their careers represent the game's evolution in microcosm. In each case, the Coach (Halas, Brown, Walsh, Belichick) was almost as famous as the QB.

On the other hand, there are some QB's who stood outside of any coach or recognziable "system": Baugh, Unitas, Marino, Manning.

Would Luckman, Graham, Montana or Brady be as successful outside their particular system? Would Baugh, Unitas, Marino or Manning be as successful if they were forced to tailor their playing to a particular system (Johnny "Field General" U playing for Paul "I call the plays" Brown? I don't think so).