The iPods are just good, real good. There are other players that are better in different areas, but the iPod is a reliable, known factor, and easy to use, especially if you use iTunes.
For myself, I chose the Insignia ns-dv4g, a 4 gig flash player. I love it, great player and it has two headphone jacks. It was a great player, but going with a non-ipod, i could have just as easily ended up with a lemon, like I did on the player before that (A Kanguru 512 meg flash player that was slow and sucked). If you get a non-iPod, try it out in a store first to make sure it's good. The iPod is the only one I'd say you could safely buy and enjoy without ever seeing one. That's not saying it's the best, but it's definitely not the worst.