There is a W3C Quality Assurance tip about this topic:
<h1>
is the HTML element for the
first-level heading of a document:
If the document is basically
stand-alone, for example Things to See
and Do in Geneva, the top-level
heading is probably the same as the
title.If it is part of a
collection, for example a section on
Dogs in a collection of pages about
pets, then the top level heading
should assume a certain amount of
context; just write<h1>Dogs</h1>
while the title should work in any
context: Dogs – Your Guide to Pets.