While crit is best dps stat, I wouldn't definately recommend it for progress, since crit offers no defensive value. Top ranked dk's just go with crit since they and their healers are just so overgeared that they're able to do that.
Stack parry and dodge because the new riposte ability causes you to get crit equal to 75 % of your combined dodge and parry which means little bit less crit than full crit build but you will actually be able to tank something without going splat in seconds. Can't post links yet but you can check my dk's armory which is Doge - Twisting Nether EU. With my gear I have about 40 % crit chance when riposte is up and I generally pull 200-350k dps depending on fight.