PLEASE don't take this as an insult.  After playing around with numerous sites I've come to realize that unique titles and descriptions for pages mean a lot if you want a lot of love from search engines.

I manually updated the core to get descriptions tags. What I did was in default.ascx and default.vb changed the description tag to be a control. So in default.vb it sets it to the default description but in any module I can refer to the control via its unique id I gave it and change its description.

I would be nice if the core could add this update to allow for us to dynamically change the description if we like.

As far as the forums would go, I'm not sure you want to put any of the forum post in the description field (maybe forum category and title).  But for the title, for SEO, it would be nice for it to follow this format:
[Forum Post Name] - [Forum Category] - [Portal Name]
ex title: "Search Engine Friendly Forums - Forums - DotNetNuke Projects"

One suggestion I made awhile ago was to have attributes in the PortalModuleBase  for setting the page.title or page.description and other meta tags such as page.enableSearch = false (to generate the meta tag to prevent spidering of that page). However, it was pointed out that PortalModuleBase is at the module level and not page level and so two modules could both try to change the same headers. I'd still like the option though....

My customized forums and events modules both have customized titles and descriptions for example.

Jason