Saving the best for last....
There were several people standing outside the entrance to the Keep just above Bael Modan in The Barrens. None of us were high enough level to survive it on our own, and most everyone else was a warrior. Along I come with my Tauren Shaman, and they decide that with me as a healer, we might be able to clear it. All is agreed, so in we go.
Things are going well. We're kicking butt, I'm healing and doing some occasional damage, communication is great, and everybody's playing their part. We get to the bottom of the place and are faced with a lvl 30 boss and two lvl 25s at his side. We're all low to mid 20s, so this seems like a gamble no matter what. While we're trying to decide on a battle plan, the boss notices us and charges. There wasn't even time to be disorganized. Three of the four of us got killed, and told the other guy to hide till we got back.
Skip ahead a few minutes, and we're all in there, standing ghostly atop each of our respective corpses, trying to finish the battle plan we were working on when so rudely interrupted last time. We all rezed, and he came right at us again. We all died this time.
Again we trudge back into the Keep, and decide this time to rez in the next room over, heal up and slap on some abilities before proceeding. It all comes together. I also decide to stay in that room and heal from a distance since somehow the boss made a beeline for me last time.
We commence the battle. It's all going well until I use my first heal on someone. The boss takes a sudden and immediate interest in me, runs over, and blam, kills me in about four hits. At this point, most of us have all broken armor and couldn't possibly even fight our way back out, let alone finish the guy we'd gone in to get. So four Hordies took the resurrection sickness penalty (no lost armor since it was all broken anyway) and went on our way.
Sure, we didn't achieve our goal, but it was such a great party that it put meaning into "It's not whether you win or lose; it's how you play the game."