well to reclarify. My guild friend Dk got 5k dps using the idiot lolol 51 0 20 spec (no diseases). He is going again as 51/13/7. He got 6.6kdps prepatch on patch25 and well, with post patch those numbers only go up. I gotta see it with my own eyes but hes one not to lie bout it.
He does have prob the best gear sides the Deadly Foe cape. also has 3 profession perks. So basically he is probably the most geared Dk.
the itemization in each spec seems pretty different for the most part (for top notch end game gear etc)