Let's contrast.
Pros of the iPod:
It's prettier (I don't care, as long as it works)
better video support (supports iTunes video... sorry to disagree, but this is subjective) (I hate iTunes video because I think it's overpriced for what you get.)
better interface (i love the click wheel) (clickwheel is neutral for me, being able to rotate to landscape mode is a bigger deal for me)
screen is same res, and slightly larger (sorry to break it to you) (too bad it's a huge pain to get video on the iPod, while the gigabeat supports WMV video, which is easy to rip.)
better battery life (up for debate. They're actually pretty equal.)
works with Macs (don't care, don't use one for my music, irrelevant to me)
has more accessories available (All I need is a headphone jack to plug into my car stereo, and some would argue not having a plethora of $30+ cases available is an advantage)
has higher hard drive capacity (don't care, I'm not going to listen to all 28GB of my music at once and don't want it all with me. I do fine with an 8gb nano, actually. This isn't really important. But until the introduction of the 5.5G they had equivalent 30 and 60gb capacities)