My guess is the required score for a section article should be 5, while a Front Page article could be between 7-10. It depends on how frequently we want articles to be published. Personally, I'd be happy with 5 to section and 7 to FP.
It's interesting to look at the moderation stats to get an idea of voting patterns. Our most read article is Axel's, which has a score of 14 from 14 votes cast, with 25 readers. Bill Sheeran and Kim Farnell's articles are more indicative of what we can expect, given that many people read Axel's article on our first day and probably haven't been back for a few days. Bill's has a score of 8 from 9 with 18 readers, while Kim's has 9 from 11 with 17 readers. You get the idea.
Given these factoids, what are your thoughts? The attached poll might give us an idea, but feel free to comment.