A multiplayer game, but not an MMO, which contains all of the following:
1) Mechanically intense fights against swarms of enemies and massive opponents (So like Dragon's Dogma, Dark Souls, etc.)
2) RPG Style character creation, stats, equipment, skills, etc. Because number crunching is fun.
3) Focus on or encouragement of teamplay. You can't just do your own thing, or you can but it will be harder. Work together to take down that giant ogre and survive the onslaught of his goblin army!
4) A robust crafting system. Equipment, potions, etc. can all be acquired through play, but the stats are better and the consumables more efficient when crafted.
5) Player housing. Build your own house, castle, whatever. Have a full base for your team to live in. Minecraft style, I guess.
6) A large world to explore, with the option to mod the graphics to make it beautiful and stuff.
7) NPCs and a quest system.
I can usually check like 3 or 4 off after a while of searching, so I might find a game (*cough*Wurm*cough*) with building, RPG-style character creation and crafting...but it's got no NPCs, combat is incredibly uninvolved and the world isn't terribly fun to explore. Which is cool, it's probably fun, but it's lacking elsewhere.