This is a slightly silly comment, but I'll explain why I think it's worth making.

The best answer, of course, is don't make mistakes!

Of course, we're all human (and, ahem, it's not like I haven't had to correct papers which have already been published).  However, I continue to be amazed by how sloppy some papers are which come to me as a referee.  These are often by serious, established mathematicians.  But I'm talking about people managing to cite their own work incorrectly (or get a definition, which they invented, wrong), or major, paper-breaking errors which I, as the referee, spot almost immediately.  I can only imagine that people, once they have proved a result, almost fall over themselves to write it up and send it off.  I'm young, and relatively patient, but I imagine that this behaviour is a good way to get rejected out of hand (even if the, corrected, paper is quite nice).

To answer the original question: as a referee, I would prefer corrections, but I would agree with Pete Clark that this would make me lose faith in the author(s).  If I were an editor: I don't know...