Local notification sound is a mistake.
 

Please a) change the local notification alert to something other than the new voicemail sound b) allow user to choose from five sounds.

2Do does a great job here. I can choose from six very pleasant, unique sounds. If you insist on just one option I would suggest you search OS X for "Sonar" as it has a pleasant melody.

Thanks team!

The user must be able to identify audibly what the iPhone is doing. I must know when I have a voicemail while a task do can wait a while.

I agree that the sound should be unique, I prioritise tasks over voicemail.

I think that the ability to choose the sound would be better.