An original signature tailored to the email, no matter how brief, is a small reminder there is a human behind these three (or four) paragraphs who is worth your attention.

This is why I've never used a default signature. I type it by hand for each message, including whatever other information (company name, contact info) that is relevant for the recipient. I'm not sure if people notice, but it helps me remember that my words are going to another human being.