PicLens, a plugin for Safari on the Mac, is pretty darn cool. It only works with a few sites (Flickr and Google Image search, notably), but it gives you a really cool way to navigate through image search results. Basically, if you're on a page it knows how to parse, when you click on an image it'll scale up to take over your full screen. Other image results will show up as thumbnails along the bottom, and you can search through them, kind of like iPhoto's full screen mode.

The only minor annoyance (other than that it only works with a small handful of sites) is that it seems to screw up the tab highlighting in Safari, so it's hard to tell what your current tab is. Boo :(.