My buddy Dorkknight did a good bit of research on what is a good tanking build. I don't know if things have changed since I last played with him but this is what he told me. If you do the proper blood spec then you are a great main tank and boss holder, you have lots of self healing so it helps keep you going. If you do the proper frost spec then you are an excellent off tank since you have more aoe abillities so you can pick up aggro on adds quicker and easier. If you want a good build for tanking, just look up Dorkknight on Armory, he usually is in tank mode so you should get a good spec off of him. I know he checks out the Elitist Jerks website to get info on tanking.