Playmate = Helpmate
Mindmate first, because without understanding and being able to communicate, you wouldn't have much. Playmate and Helpmate equal second, because if you can't have fun, things will get stale very quickly. And if you can't get through troubles then things won't last very long. Someone with different ideals could be interesting, and provide many interesting hours of debate, as long as they aren't totally a black/white contrast to yours.