Flash can be a good thing for your actual gallery, since it will protect your images from Save As.. and it makes a nice clean interface for viewing and preloading a bunch of images.
I wouldn't reccommend creating an entire site in flash, though. If you're going to have supplementary pages or pricing info, I would use HTML to do all of that work. Keep in mind that there are still some people out there who either don't have flash installed, or have an old version of flash installed. Trust me. I hear about this a few times a week at my work.
This may not be a major thing for you, (It depends on whether or not you're hoping to generate traffic from web searches) but when a site is done up in flash, search engines like Google, etc. can't follow any of the links in your site, basically meaning that they skip it and it won't get indexed.
My preferred design would be a tableless HTML setup using Cascading Style Sheets (CSS) to organize the formatting of the site. Unfortunately, that's just one more thing you'd have to learn how to use before completing your site. If HTML w/Tables will get you to a completed site sooner, I'd say you should go that route.