Don't listen to anything John Dvorak says, he's been an anti-Mac and anti-Apple pundit for years now, so him spouting up about iPod competition is nothing new. Every year the story with him is a new way that Apple is going to be driven out of business, just do a Google for "John Dvorak" Apple, and you'll see what I mean.
Plus, there's no competition for the iPod. It's already got the market cornered, it doesn't matter if other products have more features or cost less, people will pay more for the iPod name because they know it means quality. Don't ever listen to John Dvorak, he's just going to keep shorting Apple until he's right some day. But that day's not coming any time soon.