Go with X.

Reasons:
1. Pretty boy hero. Chicks dig pretty boys.
2. Easy to get battle system. Seriously, no crazy explaining necessary
3. Love story
4. Love story
5. The laughing scene. If you can sit through that unbearable moment with your girlfriend, you should probably go ahead and get married.
6. Sphere Grid: If your girlfriend can't figure it out, you'll know to dump her. It's more of a weeding out device really.