4e
I was skeptical about 3e when it was first announced but WotC sent out some early announcements and guides that impressed me. Eric Noah's site was also a big help. And, in the end, WotC won me over to the new edition.
So I was excited when the 4e announcement came out. Plus, a friend of mine was working on it (we were working together when he left for the job at WotC). But the early information coming out did the opposite of what it had done for 3e - it just showed me more and more that the upcoming edition was not what I wanted. The marketing was terrible. And the end product was extremely disappointing from my perspective. It was the D&D that I was never looking for.
In the end, we played it because a couple of players in the group were really interested in it. But after 9 months, we were all pretty united in deciding to go back to 3e.