There is an old WebmasterWorld thread on the topic of how many header tags (i.e. H1, H2) you should have on a page and how you should use it. The thread was revived yesterday when Matt Cutts of Google answered a question on that topic on video. Here is the video:
So there you have it. Don't wrap all your content in the H1 tag. You can use it multiple times on a page but use it for page heading above paragraphs of content. Don't over do it.
WebmasterWorld's Tedster disagreed a bit with Matt, he said:
Even though Matt say s it's "OK" to use more than one, I'm still a big fan of using only one H1 element. If it seems like two are really required, I almost always make that content into two pages. Or if the content is too thin to support two pages resonably, I'll figure out a single over-arching headline that can be the H1 to support multiple H2 tags.
I find that approach also "packages" the semantic signals more effectively. That's kind of the way I understand websites, pages, and even code. They are all ways of "packaging" data and information, and we are all packagers.
Forum discussion at WebmasterWorld.