A gentle soothing voice, quality podcast, an excellent podcast from A Quiet Minds, Robert Jackson.

You can check out His podcast here.
As well you can subscribe on iTunes. ( Number #4 In OZ. (at time of writing) )

itunes - podcasts
look up following:
white noise meditation
guided meditation
new zealand nature sounds
i also like enya, enigma, nature sounds, and a great guided meditation but can't remember it. rikki I think