Professional pet peeve time:
Email signature areas are meant to include your contact information, not to serve as your static "good bye" because you're too lazy to type something. And guess what.... "Warm regards" sounds as inviting as cold oatmeal or a limp handshake.
You can see it in people's email like you could see it in their eyes. "yeah, I'm writing you, but I couldn't give 5 more seconds to you to come up with an original closing line like "thanks for your help" or "Have a great weekend" so I'll just leave you with
Bladie Blah Company
It used to be that emails were the standard for quick answers and confirming details, but we still wrote real letters where the courtesy and professionalism was kept. These days emails are becoming more and more accepted as the standard communication so the same professionalism should be applied. Believe me... we can see the lazy and apathetic approach in emails just as we did in regular letters.
OK, morning rant over.