IE7 appears to ignore pre { overflow: auto; } (which doesn't surprise me much but a quick google search before I posted the first response didn't turn up any information on how widely this is supported like I had hoped). FireFox 2.0.0.7 just wrapped everything so I had to go re-find userContent.css and remove pre { white-space: -moz-pre-wrap; } from it (and then restart FireFox which took two tries, bleh). (And that shows another route to go for those more nostalgic than forward-looking.)

So, it is an improvement (though I'm sure some will dislike it and need to override it with their own CSS) but not a perfect fix either. Adding to it an item for what PerlMonk <code> tags emit would help alleviate the problem of FireFox still not supporting soft hyphens.

There is also the possibility of filtering PRE tags similar to how PM filters CODE tags, a long-standing to-do item...