For those of you who aren't interested in buying into all of the iPod hype The SanDisk Sansa Fuze is a nice alternative.

Hardware wise the case is very sturdy feeling, metal not plastic, the navigation wheel has a nice feel and you can spin and click it with ease.  I like the on/off switch on the side, you won't accidently hit it and can turn it on or off quickly.  The data/charging cable attaches on the bottom which is a good location.  The head phone jack is also on the bottom which is a little awkward, when using it with a docking station or something similar it ends up sitting on the headphone...