Sheamus. Easily. His reign has not ended yet, so anything could happen, but it has already been memorable unlike Henry's reign because it was the worst World Heavyweight Championship reign since Khali. Henry's reign was awful and I cannot fathom how anyone liked it. He cannot be taken seriously as a top guy and his matches are boring. Henry's feuds with Orton, Big Show, and even against Bryan were all so boring. They tried so hard to make him into this "intomidating monster" but all his promos did was make me laugh at him.
Sheamus, on the other hand, 100% deserves his reign. He has good matches, great promos, and after only a couple of months has been far more entertaining than Henry was. The Bryan feud was great, as was the Fatal Fourway at the last PPV, I am even looking forward to the upcoming Del Rio match. With Sheamus' reign I anticipate each match, whereas with Henry I fast forwarded past most of his matches to spare me further boring torture and only anticipated him losing the title. You guys who picked Henry are entitled to your opinion but I strongly disagree. I just don't see it. Henry is boring AND a joke. Not a very good combination when looking for a potential World Champion.