One of my personal favorites is Flickrleech, a simple site that pulls up as many as 200 Flickr thumbnails at one time.
You've got a few search options here: you can go with your basic Interestingness stream, by username or user ID, Favorites, by specific photoset, etc. Anyone who plays with Flickr on a regular basis will really appreciate how much easier it is to view mass quantities of photos, instead of tapping the "more" key every two seconds.
