A social bookmarking plugin could be handy, too and a custom smiley plugin is useful if you want to, for instance, do something like "Now take the pen tool en_tool: and draw a path around...." and have an icon of the pen tool pop up there. Much faster than adding an images of the various buttons all the time.
Really, though, I ran a photoshop tutorial site on wordpress for, almost 8 months I guess (just sold it) and didn't really find I needed any plugins specific for tutorials. Depending on how you want your site to behave, or what you want your users to be able to do (comment? rate? bookmark? etc.), you'll want to use plugins to accomplish those goals... but treat it the same as any other blog.
Josh is an anomaly rails & work & twitter Organization is the
death of creativity.