Whenever I create a new Web Form on Visual Studio 2010, the default name is always \"Default.aspx\". This is a slight pain as I\'m having to change it to \"Index.aspx\" each
You can by modifying the associated .vstemplate DefaultName element. For example, you might find the webform template you need to modify in a directory similar to the following: C:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\ItemTemplates\CSharp\Web\1033. Each template file is managed within a zip file like WebForm.zip. Unzip the contents, modify the .vstemplate DefaultName element and reapply the changes to the same templates folder. Your updates should be reflected in Visual Studio. (You might need to restart VS.)
As an alternative, you should consider creating your own template (based off the original) instead of modifying the default template.