Here are my favorites:
Ajahn Brahm's guided meditations: http://www.youtube.com/user/DhammalokaMeditation
His metta meditations are especially good!
Here's one of them: http://www.youtube.com/watch?v=Evx5X8g7prM
I also like Tara Brach's guided meditations. This one is a Vipassana meditation with peaceful background sounds: http://www.youtube.com/watch?v=XHhDCW4Q1Rc
With metta!
