Unable to View this Email?

People! Why are so many email marketers still making the mistake of kicking off the text of each and every promotional email they send with the line "Unable to view this email? Click here to view..." or words to that effect?

What's wrong with this picture?

You're using the most premium real-estate in your email to solve a problem that doesn't exist.

Okay, you're trying to give your customers an alternative to viewing your message in an email client that "breaks" your nice html...