I voted other.
Technically, it should be played earlier editions, but...
The first day I played any RPG it was me and a couple of friends from work. One had bought these two 'new' games, Basic D&D and Traveller. The two of us who didn't own them made D&D characters and played for a bit, til there was a rules dispute that got a bit heated. So we took a break and made Traveller characters (mine died on the last roll, so we junked that rule in a hurry!) and played that for a while. We liked the idea and agreed to play more of both. I have no idea what we played the next time we got together, but we ended up playing a bunch of other systems. (I cut my GMing teeth on Runequest.) 
In fact, we were (with others we'd sucked into the group by then) making rules of our own based on a hodge-podge of systems (often starting with Melee and Wizard), trying to come up with the 'perfect' system of our own. So how did we end up as D&Ders? Simple, money! That's right, we bought the AD&D rule books, then decided that with such an investment we were darn well going to get our money's worth out of them! (If Steve Jackson had gotten The Fantasy Trip out just a few months earlier...)