It looks like the Mighty Mouse might be the only wired mouse that Apple will be shipping in the near future. The Drunkenblog has a report from a reader that the Wired Mouse and Keyboard combo and the Mac mini with Wired Mouse and Keyboard have been 'EOL'ed (that's End of Life, meaning they won't be available after the current stock runs out).
The Wired Mouse is to be replaced with the wired Mighty Mouse, or at least that's the theory, which makes sense. If I were Apple (and believe me I dream about it every night) I wouldn't want to have to make 3 different kinds of mouse(s). Now, you traditionalist out there that only want a one button mouse need not fear, the Might Mouse is configured, by default, to act like a one button mouse so you can ignore all the other cool features if you must.