I loved reading through the manual for Morrowind with the copy we got on the original XBox. I read all the class descriptions, details about the schools of magic, and had a whole character planned out before starting the game. I didn’t get into tabletop gaming until much later, but looking back, that manual really captured the same feeling of reading through the D&D players handbook and picking out a race, class, background, etc.
I think that feeling is why it’s still my favorite PC game.