Dave has an old school iPod that he loves to use every day. Leo says that what killed the iPod is music streaming. It's the HBO model and everyone likes having access to more music, even on a monthly basis. It's really a commodity now. It's not so much a work of art anymore -- it's a service. But Dave can't access the service with an old school iPod. He'd need an iPod Touch for that, or use his mobile phone.
SanDisk still makes MP3 players, and since Apple has eliminated copy protection, it's an easy process to move them over. But if Dave's old music has copy protection, then Leo recommends signing up for iTunes Match ($25), which will replace all of his copy protected music with unprotected 256 bit AAC files. Then he can use them anywhere.
There's also the Pono Player or the FiiO.