In these days of email and instant messaging, letter writing is becoming a lost art, and especially the formal letter. I’m pretty sure that formal letter rules are still taught in schools, but very little of it sticks. If you’re an executive or other high_ranking person within an organization, you can probably rely on your secretary or assistant to handle the niceties of letter writing, but for everyone else, knowing how to write a strong letter ourselves is important.
When you're writing a business letter or sending an email message, it's important to close your letter in a professional manner. The ideal ending for a business letter conveys your thanks and respect, without eccentricity or an overly familiar tone. Although it may seem old_fashioned, most business professionals expect written correspondence – whether via a letter or an email – to be written and formatted in a conservative manner.