Sitecore 7 Search by base templates
Quick tip, when using Sitecore 7's search API to build a general site search, you may want to return only pages rather than any other items within Sitecore. All my page items inherit from a base Item to implement page title, meta data and so on. Using linq we are able to check whether an item is based on a specific base template, to do this we need to tell Sitecore to index the base templates.
By default in Sitecore 7 indexing base templates is disabled to improve the indexing speed. This is very simple to switch on.
Inside the section within your index uncomment the line below.
Rebuild your index and these base templates are now accessible in your search result class.