WHen people say "Dining Plan," they usually mean the
Disney Dining Plan. This is the only one available to
DVC members at this time....well, the only one that uses the word "plan."
If you have an annual pass, you can purchase the Disney Dining Experience card which gives you 20% off at most TS restaurants and a few CS restaurants. It costs $60 and is good for a year. For FL residents, I believe it costs $85.
The silver and platinum plans are entertainment and food plans. They include things like boat rentals and other paid entertainment venues as well as food, and are significantly more expensive. As far as I know, they are not available with DVC stays.