Be aware that a flash site will mostly attract other photographers, not buyers. A recent report by PShelter, questioning over 500 buyers showed that 96% of the buyers hate a flash site. Flash is also very bad for SEO: it is search engine unfriendly. Of course you can add a flash slideshow or banner as an element, but not all flash on the landing page. Beware for only the "loading" progress bar on a landing page as most of the buyers click away after 5 seconds. You can find a compromise with an escape link to a non-flash HTML version of your site.
The PShelter report also has very useful tips on photography site design, like how to navigate, organization, size of buttons. Today PShelter issued a new report about SEO, specifically for photography sites.
You can not download those PDF reports, but they will email it to you if you submit your email.