What world of warcraft class should i use? (haven't/just bought the game)?

when it comes to gaming (and true martial practice as well) i am a one hit kinda guy, and being a noob, i would like some help selecting a class, i would like survivable defense, (either through evasion or blocking), strong (buffed up?) attacks, and of course the speed to do so efficiently. any suggestions from you "veterans"?