I guess it depends, if your tank is low on Defense, I'd say get him some crafted gear atleast. It's pretty easy to get to 540 though (even as a DK with the new Rune). This does bring about another interesting question though ... once you hit 80, which instance first? IE which is the absolute easiest. I haven't had a chance to hit the new Heroics really, been too busy IRL. But I know with BC Ramps was not the easiest (for me anyway) Mechanaar was where it was at in the beginning.