If I had to choose any of them to be the best would have to be Elder Scrolls:V. I knoow it was pretty predictible but you have to admit it really is good. Although all the other ones are clearly good the only one that came close was Elder Scrolls:IV. The only thing that stoped it was that it was that it wasn't as adventurous and you couldn't fight dragons. But you did see only one dragon, well it's better than nothing.