Thanks for the info. Yes, it's true... a person's height does not really determine the size. That's counter-intuitive, but it's starting to make sense.

I got measured today and, sure enough, a 54 is for me. I may be able to borrow a 54cm Roubaix Expert Triple this weekend and see how I feel on it. I already know the 56 was too big but I loved its smooth ride. I need a comfort geometry road bike and if this one fits me, it may be the one. I'm not sure though if I'll go for the Expert or the Comp.... I'll see how I can cut corners on other expenses to help the decision.