heh, let me add to the fire. on a primitive level, men come down to this: consistantly trying to get laid by the most attactive female in the vacinity. constantly trying to 'one up' their friends or their last 'laye' so they can rein supreme in the world of sex! (course, half the time they dont' see that bored look in the woman's eyes while they are pumping away!)
women however, base their choice's of the opposite (or sometimes, same) sex on status. as much as they will disagree, there is a little chip in the back of their head and subconscience that constantly will make them enquire into their possible life-mate's status. whether it be job, car, money, security or simply if he is the most dominant male in his heard.