Probably the hardest non-WoTLK fight for me was Brutallus of all things. He just did so much damage I had to bring in Merc. When I tried Vashj you couldn't move with the cores--I might go back and finish it now that I know

I solo'd 10m Ulduar up to Vezax over the past two days. Once I learned the fights it was a cake walk. Vezax I think is just going to be an impossible fight for a melee team. Oh well.

Oh, and the first boss in Sunwell? Just portal all your DK's in the first chance you get. I was able to one shot him first time with no issues.