Regardless of what you come up with as your "style guide", enforce it with perltidy. It has so many options, I think that it'd be hard to find something that you would want to do that it is unable to handle. I wrote my .perltidyrc a couple of years ago, and haven't looked back since. Plus, if this is part of a large project, you could have perltidy be part of the automated check-in process.