Should The H1 Tag Change?

I notice on vBseo the H1 tag stays constant. "SEO". My question Is it better if the H1 tags stay constant throughout the site for example a word or sentence that describes the site or change per page such as thread or forum title?

By constant i mean

Code:

 http://www.vbseo.com/page-1.html - H1 Tags = SEO
 http://www.vbseo.com/page-2.html - H1 Tags = SEO

Change Per Page

Code:

http://www.vbseo.com/page-1.html - H1 Tags = SEO For Your Forum
http://www.vbseo.com/page-2.html - H1 Tags = SEO For Your Blog

Which is better? H1 Tags stay constant and H2 Tags = thread or forum name and H3 tags = lesser important stuff like first 20 words or forum description or H1 Tags = thread or forum name and H2 tags = lesser important stuff like first 20 words or forum description.

I use an h1 for both my forum name (in the logo area with css image replacement) and on the thread title/forum title.

It is perfectly fine to have multiple h1 tags, so long as it is a 'logical' heading.

I would NOT use ANY heading for firstX words. Headings are for Headings, not sentences.

OK Thanks ill use H1 for the Category or Thread Title. Also is it possible to have H1 and H2 tags on the same line?

NVM Got It,

add display: inline; into your CSS to display Heading Tags on the same line.