Just came a across a very cool gadget for anybody using Firefox (2.0 or now 3.0), PicLens (https://addons.mozilla.org/en-US/firefox/addon/5579). It’s a simple addon that for certain websites where there is a lot of images, such as photos or videos, allows you to browse these as a picture wall which you can scroll along. Which for YouTube and Flickr is great as they normally only allow you to see 1 or a few images at a time. PicLens is far more interactive and has a search function.

[update 8 jan, 2009]

Piclens is now Cooliris (the name of the developers Cooliris, Inc). They have also produced a version for the iPhone.
http://www.cooliris.com/