Currently, I've jumped back into FiveM- a mod for Grand Theft Auto 5- that allows .lua scripts, etc for servers to run locally, allowing custom gamemodes, RP, etc. It's finally got to where MTA:SA has been for years and is picking up the torch.
I see alot of people here like Survival. I DEFINITELY recommend Green Hell, for it's hard core survival mechanics. I just got down with it and logged a lot of gameplay with my friends in COOP.