For me personally, someone who is honest? Not just in general, but about what they want. It's no fun trying to guess your way around a relationship. I suppose a somewhat similar lifestyle would make things a lot smoother, but I'm not sure I'd make that a requirement. Honesty, respectfulness, compassion; those would be the big three. Being a gentleman also scores major brownie points. You don't have to pay for my meal, but pulling out my chair or opening the car door can say a lot to me. A lot of guys don't do that anymore (at least not many that I have met).