@Fa5t3r - I would try a wide range of different tones when recording and play them back to see what goes over the best and what projects the image you want people to hear. Remember that some people may be going to hear this message over and over again depending on how often they have to call you so you want it to be very pleasant and not at all irritating.
Length – if your callers typically wait 2 minutes at a time, then at least 2 minutes of programming should be the goal. The idea is to ensure the callers don’t hear repeated messages every time they call. A typical on-hold message is 4-8 minutes in length.

Most people screen their phone calls and often avoid answering unknown numbers. If you’re applying for new positions, you should try to view each unexpected call as an exciting opportunity! In the event that you simply can’t pick up the phone, you’ll want a polished voicemail greeting to let the caller know they’ve reached the right person.
Greetings can be changed using any telephone, or from the Personal Communications Assistant using a desktop computer; However, departmental mailboxes and those assigned to labs and general spaces must be updated using a telephone.