I recently found a great Internet radio source, Pandora.com. You input the name of an artist or song you like, and Pandora plays other songs like it. You give each song a thumbs up or a thumbs down. Pandora's software uses your choices to program your own personal radio station. You can have many such stations based on songs or artists you like, and you can also play an automated mix from all or some of your stations. Each song is directly linked to iTunes and Amazon.com so you can purchase either downloads or CDs if you choose – but you don't need to do this.
Pandora is ad supported. These are display ads (banners, etc.) on the page. The stations stream 100% music constantly, 24/7. But if these display ads bother you, you can subscribe to the premium service for a small yearly fee.
This is a great service with a really smooth website. Try it out before sefira – or during, if you're a bit rebellious or like classical music.