I'm currently level 25 and loving my 2H build. After doing some research, I was told the best way to level a DK was magicka with a destruction staff. I tried that and was quite literally getting two-shot by every named-mob in the game.
I respecced to stamina, threw on some heavy armor and equipped a 2H and have become a killing machine. Seriously, I'm having no problems now at all and am having a blast. Even in groups, I seem to be doing well. (Get compliments anyway). The only thing that's really lacking is good AOE. I'm fine on single-target, but I'm pretty sure my DPS drops in large pulls. I'm Ardent Flame, by the way.
So, my question is, how do stam DKs do at max level for both PvE and PvP? I don't anticipate doing any raiding, but you never know. I might decide to try it. I'm mostly just going to be running random dungeons and PvPing a lot. Stam DKs don't seem to get a lot of love on the forums, so I'm curious about their performance at max level.