DNS Names for external services

Just curious, what is your opinions of the security vs. ease of use trade-offs on putting DNS entries in (vs. making people know/use an IP address) for services you expose to the Internet.

For example, 

webmail.companynamehere.com for your webmail service

www.companynamehere.com for your web site

The two above are typically common and don't cause me much concern. What about this next one?

vpn.companynamehere.com for your employees to access your company's VPN server

It's this last one that really begs the question. Should I just as well use the name "attackmehere.companynamehere.com" rather than vpn.companynamehere.com. I searched around on the Internet, but couldn't really find pros and cons...

Just looking for opinions. There are no "right" answers ;-)

Jeff