If you could only pick one you simply couldn't maintain a healthy relationship. Good match is finding someone that you find both physically and mentally attractive. Of course it's a bit of a personal view, I know some people could date a braindead girl as long as she has good tits and ass, but generally speaking you can't go far with it relationship wise.

If I had to choose one I'd go with personality, since shallow people usually have low morals so they tend to cheat and whatnot.