We started playing Original D&D (still my favorite iteration) in 1974 in the waning of the year. I still have all of my first printing booklets.
I stopped the brand D&D when 4th Edition came out. I was working for Wizards at the time and had more than a solid idea of how the game was made and what it was supposed to do. To me, it was not D&D at all, despite the brand name.
At the point, I switched to Pathfinder and when I run games for my sons and some friends, it is that one that is played since that is what they know.
On rare, very enjoyable occasions, I get to sit down with some oldsters like me and play some OD&D. Now THAT is roleplaying.