Like Greg Kuperberg, I think of this as a small stylistic point compared to many others. For me it's more important to choose numbering of sections, subsections, equations, definitions, and such to maximize the reader's ease of understanding what is going on. Some built-in LaTeX styles used in books and journal articles work against readability. Typical is a reference to Proposition 7 or 3.7, which may be hard to go back and find quickly (especially if Proposition 3.7 occurs in Section 3.4). Similarly, referring back to equation (38) may send the reader on a lengthy hunt through the previous 40 pages of a long article. Also of dubious help to the reader is consecutive default numbering of the sort: Definition 1, Theorem 2, Remark 3, Lemma 4, Definition 5, etc.