In the related links section below are two builds, one for tanking and one for dps'ing.
Death Knights can be a tank and dps. It all depends on where they spend their talent points and the gear they have. They may not be the best main tank, but they are defiantly great off tanks. In the upcoming expansion Cataclysm, due out in late 2010, the Blood tree will be the tanking tree.
Envenom with the build that is in the related links
It depends what you want to do. For PvP, I find a destro/demonology build best, but if raiding an affliction/demonology build is brilliant.
the best ship to make is the type you want i would rather have shield rater than speed
After release, they were known as op, however the got neffed. Theres no best class as all classes have their own features and specialities.
His lack of talent is his best talent
They are the same just pick shadow meld or sprint.
the best thing in a knights life is thay have a family that cares about tham
Blizzard designed the Death Knight as a class for which you could combine talents from all three trees to tank. As WotLK progressed, however, it more and more turned out that the Frost tree (Dual-wielding and Mitigation) was the tanking tree to go for. One single talent never makes a tank, it requires a combination of talents to get there. Talents like Toughness, Improved Frost Presence and Unbreakable Armor help mitigate damage, while the various cold-based and dual-wielding talents improve your threat. From the Blood tree, Blade Barrrier is a good talent to take, and you may look into some of the others for Threat or health regain. The Unholy tree features Anticipation, which increases your Dodge, and Morbidity, which increases various effects of Death Coil. If you go down this road, you may want to take the Lichborne talent from Frost, as you can then use Lichborne to become temporarily undead, and heal yourself with a Death Coil if needed. In most cases, high-end tanks nowadays are Frost/Unholy, but once the next expansion comes, Blood will be designated permanently as the tanking tree for Death Knights.
War.
Talents are a special to a person.Try something new.You will find your talent naturally. Hope This Helped! :)
Lancelot is generally accepted to be the best warrior of King Arthur's knights.