Not all metadata properties make sense to template. For example camera specified properties such as shutter speed and aperture will change for almost all images. However properties such as your email address may change infrequently so is a good candidate to templated in the base template. Other properties such as location may change per shoot but that means all the images for that shoot can be templated in the current template.
List of all Templated Properties
Description
Label - Label of the image
Title - Title of image
Subject - Subject of image
Description - description of image
Rating - default rating
RatingPercent - default rating percent
Keywords - default list of keywords
Tags - default list of tags
Comment - any default comment"
Author - Your name
Copyright - Your Copyright
Camera
Maker = Camera make
Model = Camera Model
Location
Latitude = "Latitude"
Longitude = "Longitude"
Location = "Location"
Scene = "The scene in the image"
IPTC
SourceUrl = "Some Text"
UsageRights = "Private"
CopyrightUrl = "IainFerguson@idk.co.uk"
Headline = "Headline here"
Category = "The category of the image"
Source = "Source of image"
Instructions = "Some Instructions"
Creator = "The creater"
JobTitle = "Your Job title"
Address = "Your addess`"
City = "Your City"
State = "Your state"
PostalCode = "Your Post code"
Country = "Your Country"
Phone = "Your Phone"
Email = "i.ferguson@idk.co.uk"
Website = "www.YourWebsite.com"