We wiped on Garalon's LFR pre-nerf. After the first two times, myself and a guildie figured out the pheromones, but then we didn't have enough DPS, and after a few hours of trying, the group fell apart.
Also, Madness, when it first came out. LOTS of fourth platform wipes. I think it took like 3 hours for me to kill Madness the first time. >.< I remember my guildie going in after me and getting the achievement before I did, and I concluded I just got a horrible group.
Other than that, no wipefests. And I'm not counting player-initiated wipes that are caused by assholes HoPing tanks or life gripping over the platforms in madness or whatever.