Well I guess it all depends what kind of websites your looking at, or what "circle" of web design you involve yourself in.
Alot of the stuff I do, and the design community I participate in does a HUGE amount of Flash.
There are two basic ways for someone to e-mail you from your website. There's the "mail:to" function, which you described. This actually opens the user's e-mail client and "prefills" certian fields which you can dictate.
Ther other, which is what I use, is a PHP Form Mailer. This way, the user is NEVER prompted for their e-mail address, it doesn't involve their e-mail, nor their e-mail client. The PHP Code takes care of the "mail" functions.
This type is the kind of form you see on sites that often have a "Contact Us" section. A form where you fill in your name, whatever information they set it up for, and then a general box where you can type your question or whatever. When they hit submit, it e-mails the contents of the form to the webmaster.
This is my personal preferred method. If you would like a copy of the PHP Code, let me know. I have a bunch saved, and once you get the hang of how it works, you can customize it to include/exclude whatever information you want from the user.