(This didn't post yesterday for some reason, so here it is today.)
The first edition I really didn't enjoy was the 3rd edition. It was the first edition I didn't bother purchasing after I looked at it. I didn't care for the increased power levels and the fact that some of the character classes were relegated mainly to support positions. (I'm looking at you, bard.) I really didn't like the concept of buffing. I thought it made everything play too much like a video game. (Which, of course, means I really didn't care for 4th edition.) I won't go so far as to say these were bad games, but they weren't for me.