For sound quality the iPod almost never wins comparisons to either the Creative Labs or Zune. But through those tiny ear buds that may not matter to a lot fo people. Creative Labs Zen now supports FLAC codec which is great since it is a lossless codec and provides great reproduction, though at the cost of storage space.
When I bought mine about 18 months ago I did about a month of research adn the Creative Labs Zen was consistently the player reviewed with the best audio reproduction. To me quality of the music was of supreme inportance.
The Zune also has great sound reproduction and the new one has massive storage as well.
And the Sansa line is remarkably high quality for the price.
Are you kidding me? Seriously? "Sound quality"?
So when I was listening to songs on my iPod with my Beyerdynamic DT 880s or Senheisser HD 280 Pros via a CMOY amp, the Sound quality was worse than say, a Zune, or a Creative Zen, or a Sansa, or my Turtle Beach 5.1 surround sound card?
That is all.
iPods are fine, I've had all of mine die on me after the warrany ran out, switched to a tiny Sansa, works great. It really comes down what features you want/how you like individual models. Every mp3 player that you can find in a mainstream store (Best Buy, Target, Walmart) is most likely perfectly fine and amazing in its own way.