This site has a good collection of music videos, from it I discovered one of the best female singers of all time - Eva Cassidy.
I chanced upon the best version of "Somewhere over the Rainbow", a duet by a current singer and a past (deceased) singer. I was really awed by the singing talent of Eva Cassidy - so I went on and searched more on her. Dont miss this, if you havent heard her now's your chance ;)
More on Eva on ABC nightline videos.
Of course, no need to go blog-hopping if one wants only to listen to music, there are more sites like this with endless choice of songs.