For me it's Diablo II. Granted I've played my fair share of D2 since launch, and also recently on a private server with a comrade from hexbear, but I still feel like years later the game didn't grab me as much as D1 did.
Granted I don't hate D2, but for a game that I keep coming back to, D1 takes the prize.
Castlevania Lord of Shadow. I only played about 2 hours of 2 but it was such an awful departure from LoS. We’re due a new Castlevania…