Obviously the best plugins are going to depend on what you want to do, but here's a few I recommend for everybody: feedburner redirection, spam karma or askimet for eliminating comment spam, database backup (which I think comes with WP now), wordpress reports, ultimate tag warrior if you want to use tags in addition to or instead of categories, and FAlbum and/or Flickr Photo Album if you want to use your flickr photos.

As an aside, though I use and love wordpress, I would recommend checking out pixelpost as your photoblog CMS.

I've used it for a photo blog I setup for a friend and it works great.

The only reason I say this is that because it is actually designed to be a photoblog cms so it just makes more sense.

However, you can manipulate wordpress enough to make it work as well.