For many geeky guys, this turns out to be a self-indulgent view that will virtually guarantee that they'll spend their life alone. I've met plenty of guys who think that they should just be able to find the video-game playing, D&D-, MtG-, hard scifi-, Linux-loving girl geek of their dreams. If they can, more power to 'em! On the other hand, I'm willing to bet that their chances will be significantly increased if they develop a taste and passion for art and cinema and cuisine and travel, etc.
Of course, it's not going to work if you end up having no real interest in these things, but if you do, then you might take these interests off of the back burner.
Another common fallacy is that you can weigh 300 pounds and yet attract a 110 lb waif. It's been known to happen, but the odds are stacked against you.
Yes. That being said, women's tastes seem to fall on a broader spectrum than men's. If you're a skinny guy, dress flatteringly and you'll be attractive to some non-trivial demographic of women. Skinny guys can look great in a suit or more formal clothing, or they can get skinny jeans and go for the heroin chic look. Same is true for heavier guys. Take up touch football on the weekends and there will be a demographic of southern women who will be into that.