Suppose you were a guy who's in his 20s. And suppose that the following three girls all wanted to be in a relationship with you. Assume that this is intended to be a long term relationship, possibly leading up to marriage.
1] Very pretty, at least 8 or 9 out of 10. You've known her for about a year. Reasonably nice person most of the time, but horrible when she's angry. Usually a bit introverted. From a humble and modest background, but looking to move up in the world. Average intelligence, and average career. About 3 or 4 years older than you.
2] Above average looking, say 6 or 7 out of 10. Seems like a nice person, but you don't know her that well just yet. Extremely educated and intelligent, with realistic aspirations to become a professor. From a very upper-class background, i.e. parents are on speaking terms with members of the Royal Family, have hereditary titles etc. One year older than you.
3] The least good-looking of the three, about 3 out of 10, but can be kind of ok if she makes an effort. She's been your friend for several years, and you both know each other inside out. Currently studies in a foreign country, but not for much longer. Above average intelligence, and looks set for quite a well respected profession. From a middle, or upper-middle class background. 4 or 5 years younger than you.
Which one would you pick, and why?