Pretty emails to users

Is there a way to improve the emails sent from the wordpress registration.
At the minute, mine look really ugly, plain and even have an email address that is reference of the servers host account as opposed to my URL (can I change this?)
Wht I would really like is (besides the from email address being one I choose) a pretty HTML email with a banner and some fireworks and sorts : )

Can anyone suggest how I should do this?