Hummm... I consider 1e and 2e to be the same and stopped playing that for 10+ years because I found them inflexible and limited compared to other games out there.
I have been playing 3e since January of '03. And have been enjoying it very much. Although not as free as other games, it did address a number of issues I had with 1e and 2e.
I disliked 4e almost from day one. Let's leave it at that.
My personal jury is still out on 5e... (I'm not over excited by it.)
So 3e/3.5/Pathfinder is definitely my favorite! With Pathfinder really taking the cake. I'm sure there are people completely floored and surprised.
Finally an easy and obvious question!