Now for my reasoning on why subs should be after (an implicit or explicit main) - it's easier to read. I love to read - newspapers, magazines, web sites, books, code, books on code. There is a definite well designed, well thought out, and well documented approach to writing - it's called the funnel method where the first paragraph is your general outline (moving from general to hypothesis with each sentence). Succeeding paragraphs are the specifics that support your hypothesis. I strongly believe code should follow this method because coding is just another form of writing and communicating. Think about it.

I guess that depends whether you're a "top down" or a "bottoms up" programmer.