What was the first CD sold? Answer: Billy Joel's 52nd Street, which had been previously released on vinyl in 1978 (I actually have both the vinyl and CD version).
Although pre-recorded CDs have certainly lost their luster with the convenience of digital music streaming and downloads, it was the CD that started the digital music revolution. I still love CDs - I buy and play them regularly.
For more info on the history of the CD, check out the report from CNN.com.
Also, check out a photo and a complete review (written in 1983 by Stereophile Magazine) of the first CD Player sold to the public.