Originally Posted by mjtaylor

Actually, I like h3 tags and I do believe they have SEO weight. I use them only when they are actually logical.

One of the places that h3 works is to breakout quotes from within the text, as sometimes done in magazines. It's a great way to add some keyword power both for SEO and human marketing impact.

As others have noted, only one use of h1 per page, and logically it would be "close" to your title tag, but it could be a variation. Think in terms of very closely related keywords ... for example, your keyword might appear as a stem word in the title.

Example: Title: SEO Website Design
H1: Websites Designed with SEO in Mind ('designed' is a stem word of 'design'.)