Thank you for calling {insert company name}. Please choose from the following options: If you’d like to speak with the operator, press 0. For customer service, press 1. For the sales department, press 2. For accounts payable, press 3. To listen to our staff directory, press 4. To leave us a voicemail message, press 5. Press 6 if you’d like us to repeat this menu. 4. When they call outside of business hours.
If your internal greeting has been deleted, your external greeting is played to all callers. If you have no external greeting, the standard greeting is played.

If someone takes the time to call and leave you a voice message, they usually have a reason that they are calling. It does convey a certain level of interest when someone is willing to hop on the phone with you. If they were less interested, they would probably send you an email or fill out a form on your website.
I have a confession to make: I haven't recorded a new voicemail greeting in nearly a decade. Since then, I've (hopefully) become more articulate, poised, and self-assured. But hear my voicemail recording, and you'd think I was still new to the work world, a little unsure of myself — and probably not an authority.