World of warcraft DK Shaman Warrior Paladin?

OK so i know i cant be a DK will i get a level 55 guy but between the Dk Shaman Warrior And Paladin Which one can do the things i want which are...Take one 3 or more guys at one time kill them at a decent speed not die alot and is fun to play and if it is a dk which class could i evel up the fastest to be able to make the dk