Often best way to start is to build a prototype. This is cheap and very effective way of exploring your ideas and shaping them. It is also a lot of fun, both for you and for us.
Why only do one thing, let's have several alternatives and work on them, see which one is giving you what you really want to accomplish.
Prototype is a website that is made to look like real product, except that it lacks functionality and is there only to 'mock' how real website would look like. It helps clients see products 'as is finished' and explore alternatives.
We prefer to develop prototypes in PHP and Rails as this should give us minimal time spent on setup and most of time on actual prototype.