I successfully setup vBulletin (thanks Mitch!).  I set it up at site/folder - thinking that would be the best way to include other non-forum pages

...but it's been suggested that it's best in the top level directory.

1. Why is it best there?
2. If I move it there, will I still be able to add folders for html pages?
3. If best to move there, can I just move all the files from site/folder to the top level (and, of course, change the url in the admin cp settings)?

Thanks!

Aha, I fixed it! 

I removed the index.html file and all is cool now.

It seems talking to myself works 

It's not. I would say that's very bad advice. I find it's best to put applications in their own directories under public_html/. This keeps them cleanly separated from the other applications, makes it easier to upgrade or delete them, and keeps the top level clear of application stuff (just the site overhead files). If you have only one application, you will need to redirect to it (via cPanel or a simple index.html with a <meta> refresh tag) to the lower directory, but if you add more applications and "non-forum pages" you will have a nice place for your entry page with links to the applications.

Since you've already moved your stuff up to the top level, you might as well keep it there until such time that you add more non-forum stuff. At least, you know how to move it back down to its own directory.