In my development I find that I do not use the Lotus provided templates often if ever at all. But I do find that the template functionality is very useful for automatically including code, fields, agents, etc. that I use repeatedly in almost all my Notes projects. I have created a Developer's template that includes one agent that has standard declarations, error handling and Includes statements. This template also includes a form with three or four fields used for debugging and some associated views. New forms, agents, and views can be developed faster by copying the design elements in the template.
Starting from this template can save you a couple of hours for each project. Also, as you find yourself repeating other design elements in your projects, you can add them to your own Designer's Template.