You can practice relaxing with or without music. The purpose is to rest the body, not necessarily the mind. However you want to promote a positive mental environment. If you're mentally stressed, this will just influence tension in the body. Choose some quiet, easy listening music to promote a relaxing environment.
Many people can just relax as easily without music.
The most recommended music is designed specifically for relaxation and meditation. Many people prefer New Age music. Unlike many classical selections, the new age music keeps a constant tempo and volume. These modern blends of music are best for beginners. The classical and the nature sounds will give the beginner something familiar to identify with.