This has always been an interesting debate as really, there is no one answer. I'd suggest it is akin to a pair of iPads- one offering the ability to download music onto it and the other one simply does not.
There would be those in the camp of, "I don't rarely ever listen to music on my iPad so I purchased the one that is less expensive, not offering that ability."
Another camp: "I listen to music a lot and even when I don't I enjoy the freedom of being able to do so on a whim and thus spent the extra and bought an iPad that is equipped to allow me to do so."
It all boils down to your needs/wants/desires/affordability factor.
(And the GPS capabilities, as expressed in another thread, is an added bonus.)