[Bilderback]

Many templates would display but the main would be BLOG.
It depends on what area of the page you are wanting to edit.
For instance, if you were attempting to add content to the user sidebar,
that template would be blog_sidebar_user

An easy way to find template names is by enabling source code comments.
vBulletin Options -> General Settings -> Add Template Name in HTML Comments
With this above option enabled, you can simply view the source code of any page
and you will see comments describing where templates begin and end.
Note:Dont forget to disable the option when you are finished to save bandwidth.