Another way to look at "playing the role" is the way our group does. You have a character. You might have designed the character very precisely. You might have a lot of background. Or you might have been handed a pregen set of stats, which you then named. Or maybe you even had it generated semi-randomly (ala Red Box Basic D&D). Or you might have written up a bunch of (Fantasy Hero) powers on index cards, shuffled them, and given everyone a random deck, followed by some horsetrading, which you then forced into a playable character with some judicious tweaking. Point is, it doesn't matter once play starts.
With play, the character really forms. It "develops in play", and that is the only meaningful roleplaying to us. In fact, we consider it rather a badge of honor to be able to be handed a pregen, name it, and then roleplaying something vibrant off of that weak start. Contrawise, it doesn't matter how much background or "character development" went into your character sheet--unless you can use that to make something happen in play. Note this is completely orthogonal to the question of powergaming or lack thereof.
I don't pretend that our preference is superior to anyone else's as far as any value statements are concerned. But I will note that it allows us to quite happily play a wide variety of games, without changing our style, without powergaming being an issue at all, and without getting bummed over the limitations of some particular game, at some particular moment. Personally, if I were that invested in designing the exact character everyone visualized in their head, then I would stick to Hero, GURPs, or a similar system. D&D seems a weak fit, and always has been.