OK, I give up. I've been telling people not to uxzse quotation marks in links, and to use them sparingly in HTML tags. My reason is that if you leave out the closing quotes, you make a big mess. While the quotation marks are usually optional, I have to admit that the standard practice is to include them. So, I hereby bow to standard procedure and submit these as my boilerplate examples:

<a href="http://www.mudcat.org/">Click here</a>

<a href="mailto:joe@mudcat.org/">Click to e-mail</a>

Have I got it right?
-Joe Offer