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.
To be clear, no judgement there. I spend DLC money on paradox games, when I can. I'm just too poor for sims.
(the dlc can always be pirated if you don't wanna/can't spend money on it.)
why not all of it
i like to provide options is all!