I don't think this would be a very useful "general" feature for all <code> in the monestary, for many of the reasons listed, my biggest personal reason being that typically when i read code here, it's only "snippets" of code, that's short enough to be easier to read without a lot of markup.

If there was a node that really had a LOT of code, that i wanted to read with syntax highlighting, i would download it, and open it in an editor (which would also allow me to re-indent the code, something that's more important to me for readability then color.)

Which makes me think: perhaps having a user customizable mime-type sent by the server when a user clicks the "d/l code" link would be more usefull (and simplier to impliment) then syntax highlighting ... then you could either just use text/plain, or you could create your own "x-code/perl" mime type and register your favorite editor/syntax highlither as the handler in your www browser.