My LBS has someone that is trained in bicycle fitting. He uses a serotta bicycle fitting tool - it basically looks like one of those stationary bikes that is used in spin classes but everything is adjustable to get the right fit. A fitting session usually takes about an hour, costs $25, and you get it free if you end up buying the bike from his shop. He gives you all the measurements and the suggested geometry of the perfect fitting bicycle for you. He'll even give you suggestions on bikes that aren't carried by his shop. It's a well spent $25.