This kind of excitement. I've missed it. Oh World of Warcraft: Cataclysm, please know how much I love you!
We only barely killed Argaloth after about 5 or 6 tries. Our execution was absolutely flawless on all tries but the first where we learned the fight a bit, and our only problem was pulling enough dps. We got down to business and started chewing our way through him, pulling numbers I thought was impossible in heroics/normals/a few quest items gear. He enraged at about 600k and a few seconds later he was lying dead on the floor.
I don't know about you guys, but this kind of thing is what makes the game so fun for me. It was even a pug, and it's the most fun I've had in Cataclysm yet.
Edit: I just thought I'd add: 2 pieces of Vicious death knight gear dropped. We had no death knight in the group.