For awe factor, Morrowind wins hands down because I had never played anything remotely close.
The cult caves were creepy as hell. Morrowind was better at creating that creepy vibe. However, the damn sandstorms and those damn birds really ticked me off.
I loved Oblivion, but it couldn't live up to the Morrowind awe because I had just played Morrowind.
Plus they removed flight and dumbed down the god powered items.
Skyrim looked beautiful and I felt the gameplay was more refined. Problem with Skyrim was the same as the other two games. The game didn't scale enough. Too easy once you have smithing, enchanting and alchemy maxed.
Having said that, to get those three to 100 is more gameplay than 99% of all other video games.
With 2 characters, I've clocked 400+ hours on the game and never went beyond the 4th main quest. Unfortunately,I finally burned out before completing the main quest, which I will have to do one day far off in the future.