I've always felt that the one thing a girl wants is what she can't have. In other words, if you go offering your money, your face, your flock of magical geese and the keys to your canoe, you're not going to have much else to offer her and she's going to get bored. They seem to enjoy the experience more whilst they're still seeking your merits and emotions, and once they're being offered all of that on a plate, what more do they have to go for?
Also, I'm no Don Juan but I've noted in my experience that girls tend to confuse/associate niceness with boredom, which is why they'll often go for the mean guy over the nice one - they'll run the risk of being hurt for not being bored. Not only that but some girls seem to feel they're not worthy of being treated uber-nicely, and will run away from such treatment.
So it seems the nice guy who has everything to offer is fucked from the start. I personally don't try and offer anything more to a girl than the person I am. If you can manage to take it easy and not immediately offer your spleen on a velvet cushion next to the deeds for your house and your eternal soul you'll probably do better than a guy who offers everything and scares the shite out of a girl before they've even got to their second drink...