It really should take less than 1/2 second to load. Do you know how to put vBulletin in debug mode? If not, just open up your admin/config.php file and add $debug="1"; somewhere in there. Then upload that file, go to your index page and add ?explain=1 at the end of the url. That will show a breakdown of each query performed, how long it took, and etc. If you'd like to do that and post the results here I'll be glad to take a look and find out what's causing your page to take so long. Oh, and be sure not to leave it in debug mode afterwards because it could be a security risk.
Oh, and it wouldn't have anything to do with the number of templates it's calling. It would have to be a query somewhere that's taking a while to execute.