Skyrim will have more single-player replayability, while Doom, despite its great campaign, will see the most replay value through the online multiplayer, as most shooters these days do.
It depends on whether you prefer single player or multiplayer, really, as well as which of these you find more interesting;
Do you prefer shooting demons, upgrading amazing guns, and eviscerating hellspawn with their own horns while trying to turn back the tides of hell from destroying all of humanity?
Or do you like battling bandits and monsters steel-and-sorcery style, while out-roaring dragons with magical shouts, and deciding the fate of an entire war-torn kingdom as someone with Dragon's Blood flowing through their veins?