One thing that's always annoyed me about the default behavior of Movable Type is that it both requires you to put in an email address and displays it. I have no problem putting one in if it's never going to show up on a page, but I already got bit by the Radio comments stuff (my email address was sniffed out in days of me using it to post). As a result I've made a small change to how comments work. I do require that people put in their email address, url is optional. If a person enters a url it will print their name with a link to that url. If they just put in an email address it will just print their name with no link to anything.
Also, I know I could probably google for this, but how does this email encoding stuff work. In the end it's still all plaintext. All someone has to do is pattern match off the character strings for '@' and '.'. The solutions I've seen seem to feel more like security through obscurity.