Originally Posted by
asindc
A good fit is priority number one after you have chosen the right bike for you. Whatever your LBS charges for a proper fitting is worth the money. It can change your entire outlook on cycling.
I would second this, but would say that ideally, a good fit is priority number one BEFORE you buy a new bike. A good fitter can help you determine not only your best size in a given model, but also WHICH models will work best for you. Bikes have different geometries, and what works well for one person might not work so well for another.