Road cycling is a huge huge passion of mine.
I've logged 1000's of k on a few bikes of mine and it's the best way to get a low impact work out to keep yourself in good shape.
Ask yourself how much you want to ride, because you have to figure out if you even like the speed and quick behavior of a road bike.
If you know that you want to ride lots, there are really good bikes with really decent components that will work with you.
I could go into intense details about frames, components, misc equipment but it's best to read this site.
http://trektoronto.ca/buyers-guides/...-know-pg62.htm
that will help you without having to worry too much on other peoples opinions on brands and components