I have both, and the HD5 is better. Check out my thread on the subject, http://reviews.cnet.com/5208-7595-0.html?forumID=71&threadID=103650&messageID=1187409
I originally started to the thread because I was dissatisfied with my iPod and I was looking for an alternative. The final 2 posts there are about the HD5. In addition to what's there, I'll add that I love the HD5. The sound quality is amazing and really gives you the full music experience wherever you are. Something I also just came to realize and appreciate recently is also the "paint job" on the device. I got the black version and was always afraid it would scratch so I've been treating it with kid gloves. I then read a review that said it doesn't scratch easily. So I tried scratching it
Turns out the color finish is some kind of anodizing, a chemically-bonded something-or-other, and not paint than can scratch off. That's just one example of the high quality of the hardware.
Unfortunately the included PC software sucks, but it's not much worse than iPods'.
If you are the average shmo and you aren't SO into music and sound quality etc, and you want bells and whistles like a calendar and the ability to play solitaire on the subway without playing cards (I personally have no use for such things), go for the iPod. If you appreciate quality over hype and don't mind forgoing your "club iPod" membership, go for the HD5. It's better in almost every aspect that matters.
What mp3 player should I get? The iPod or the sony Network Walkman HD5. What are the advantages to each?

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