Is this becoming part of the D&D culture for you or are you picking characters and fighting like before it was implimented?
Is it becoming part of how you think of D&D?
It's always been there. There were fighters and thier sub-classes the Paladin & Ranger, who formed a front line, Wizards who blasted away from behind it, Clerics who healed, and Thieves who climbed walls a lot and occassionally got to do some real damage when no one was looking.
3e got around to formally calling them 'roles,' but still stuck to an archetypal character class - Fighter, Cleric, Wizard (though, I'd say the Sorcerer was the better-done class in that role), and Rogue. The Rogue was, frankly, still a little ill-defined, his role decidedly non-combat and tied a little too firmly to trap-finding, still, in combat he could dish some impressive damage, at times, and had some mobility. The Cleric 'role' was still tied a little too firmly to healing - and when the Cleric wiggled free of healing responsiblity, he could be overpowered.
4e formalized roles as something classes were purpose-built to fill. Defender classes /all/ have the ability to soak up damage and keep enemies away from thier allies. Defenders /all/ have the ability to heal 2/encounter, and throw out some buffs and otherwise aid/enhance thier allies. Strikers /all/ have the capacity to some some extra single-target damage, and some good mobility. Controllers, well, were wizards, and the role has kinda been crafted to keep the popular wizard class in the game, in spite of it's long history of being over-powered in some ways... but it looks like it's shaken out to be area interdiction (area attacks, walls, zones) and bestowing status effects, plus a little versatility from Rituals and the like. No role is restricted primarily to non-combat contribution, and no class is signally lacking in non-combat abilities.
The roles have always been there. The difference is 4e has made a pretty solid attempt to make sure each class neatly fits a role. Whereas, in the past, each role defined by a class, and other classes with the same role deviated from it's ideal.