We are using Jira both for internal development projects and for external support. The default email templates are great for internal projects, but for some of the support projects we need custom email templates so that the different support team can ajust the content of the mail that are sent to the users.

For instance one of our projects need a template that only contain the last comment on the issue and an official support signature. This template is not useful for our internal projects since the internal team members would like to have more information about the issue and so on.