Popular for what? Music and Video or as the "sneaker net" media ?
In the former case yes. In the latter case, USB Flash is displacing them. A quick scan at amazon.com shows a 4GB USB drive for $8. Yeah that is more expensive than a blank DVD-R media, but it is gettng cheaper each year. And it is rewritable. ( good news / bad news if trying to archive important data).
Music and Video, I would agree that most people use flash drives anymore for transferring data between computers and such.