Led Zeppelin is my go-to band for any mood. Here's two very calming songs from them, so beautiful:
http://www.youtube.com/watch?v=S4v-_p5dU34 [The Rain Song]
http://www.youtube.com/watch?v=jYpydtdlWxA [Ten Years Gone]
I like some of the other artists people listed! Jason Mraz is very relaxing along with Loreena Mckennitt (I totally used to listen to her and try to belly dance, but I looked like a fool!).
Okay, but anyone feeling down, listen to this song from Jason Mraz. I guarantee it will calm you!
http://www.youtube.com/watch?v=7l74d1fmZbw [Life is Wonderful]
Nixon, I think you will like this song. You should listen to it.
I used to wake up with the sun and ride my bike on the beach listening to this song years ago before my anxiety hit.

