My iPod, but I recently got Spotify and because my account is so new it comes under the 3 months for 99p deal, so I'm currently a premium member. But, once that runs out, I can't see myself renewing it as most of my favourite cast albums aren't on there such as In the Heights and Spring Awakening (this may be different for other countries though) plus I like the fact that my iPod is solely dedicated to music, and with that I dont have to worry about keeping storage for photos and other stuff like I do when I have Spotify installed on my phone (it took up about 3GB when i had it installed).
TL;DR I love my iPod and dislike Spotify due to its memory usage