There is a noticeable difference in the files that I have in 44.1khz, 16-bit (which are CD rips) and higher-resolution files encoded in 96 and 88.2 khz, and 24-bit.
There is more detail, less noise, the music is not dynamic range compressed like many CD’s today are.
On a good pair of headphones, one CAN notice the subtleties in the music. It does not take golden ears to hear the difference, only a good pair of headphones.
iPod Touch, Classic and the iPhone all support up to 48 khz, 24-bit as long as it’s Apple Lossless encoded, and even there, I can hear a difference between my ALAC CD rips and Apple Lossless-encoded 24-bit music with my Sennheiser HD558 headphones. The headphone jack downsamples to 44.1/16, but through the dock connector, 48/24 is possible.
The obvious answer would be “then go buy an iPod,” but I think that is a bad way to do business, and if iPod can play up to 48/24 lossless files, I don’t see why competing products should be any different. Plus I don’t really want a product that is tied up to Apple’s eco system (requires iTunes to manage).