My 160GB iPod is, in fact, the best portable music player I've ever had. It must be 10 years old, now.

However, a smart phone is the same size and connects to the Internet.

A burner smart phone like a Galaxy J9 loaded with a decent SD card is the most reasonable option.

ITunes is shit, btw. Use MediaMonkey.

I have several iPods and some no-name MP3 players. They all play the music about the same and with decent headphones (I also have several varieties) they work the same.

IMO, the difference is in loading the music. iTunes works the best.

People still use mp3 players? Why not get a disc jockey lmao.

Make sure the iPod nano 4gen is supported by the newest iTunes

No such thing as "best", everything has a style functionality to them. Apple is crap if looking for longevity and functionality, lost libary a few times using apple(still a resource though). If had to be honest for mp3 players, I have not witnessed 'best' yet, seems the device always has some user inconvenience to the device.

I liked the Creative Muvo. I think they stopped making it, which is too bad, but if you can find one you might like it and it would probably be cheap.