Without a doubt the most comprehensive, advanced, and most easily customizable gallery script on the market. Does much more need to be said?
Includes features like an online listing (with the viewer's location), full Private Message system, Comment system, precise search feature, Toplists (God's gift to customizing), pacey loading of images/thumbnails, many visual affects available, and of course an FTP import to practically instantly bulk load images to the gallery.
The target market for this was originally webmasters (because of the extent of its customizability), but it's also perfect for those quite ignorant of HTML and PHP altogether. Also integrates perfectly with the other WSN scripts, including WSNForum.