Skyrim is the best overall experience. It’s the most flexible in play style, especially with robust mod support. It’s also the only one that actually is fun to play in third person mode.

Morrowind would be second. The world is probably the most interesting. It does feel like you spend almost as much time fighting the game as enemies, combined with a lot of busy work makes it more nostalgic than fun.

Oblivion is a weird middle ground, it’s mechanically clunky in a lot of ways like Morrowind, but it doesn’t have the consistent charm. Shivering isles may have the best quest line, but it’s not enough to save the whole game.