I am currently leveling up my Death Knight as Frost and I am almost to Northrend so I want him to be my alt tank for 10 man Naxx raids and heroic runs in the near future. At level 67, it is not long before I hit up the icey shores of Howling Fjord and so I need some suggestions on what kind of gear and stats I should be looking for as I level up in order to tank heroics and do raids even. I know DK tanks are built around avoidance with defense, dodge and parry, but I don't think there is a weapon in existance which has both dodge and parry for a level 80. Getting defense capped should not be hard, but one thing I have noticed with the gear that I got on my DK now, hit rating has a huge amount to do with parry and that strength will help with dodge since you don't get shield block value. The most important thing I know about tanking is becoming uncrittable, second is spell rotation and spec (whats an ideal Frost DK spec?) and of course what kind of gear would I need to start off heroics and raids?
Gearwise just use the odd quest blues along with the BS crafted tempered gear. I hate frost tanking so I won't advise you on spec because I have little experience with it. Just hit 535 def asap and you can OT/tank heroics right at 80. You get parry from str and dodge from agi just as an fyi (Though not really enough to concern yourself with unless the items are really really close). Start running HoL as soon as you can get into groups (76 for me) for the def trinket it will really help you as you gear for heroics/raids.