It really depends on what you want your site to do. vBulletin is a fantastic forum, no doubt about that, but it's not a CMS and while add-ons like vBA make a brave attempt, they can't compete with a proper content management system like Drupal.

If your site is going to be focused around the forums, then use vB. If the content rather than the forum are going to be the main part of your site, use Drupal

Of course, you could use both with the vBDrupal addon

Alan.