Likely it will be Star Wars D6. It has lasted better as a mechanics system than the BECMI Dungeons and Dragons. Likely I will also pull out the weird and nostalgic. Fifth edition Dungeons and Dragons seems like it will have some staying power in a smaller more flexible rule set of that game.
Favorite Horror RPG: No, no, no. Horror is not for me. Mystery is good, but that may be a good thing to look for in an RPG.