All the people I've talked to (both online and IRL) who've bought a Zune hated it. With iPod's, don't even get me started on why I hate them (namely, iTunes and having to convert videos to the iPod format).
If you're looking for an mp3 player that can also do video, all signs I've seen point to the Creative Zen as being the best. At least two friends of mine have told me that they were able to drag and drop avi's directly from their comps to their Zens and play them immediately without having to convert them (i.e. it can play avi and mpg formats).
I have a 30 Gig Vision:M Creative Zen, and I love it. I didn't want to be saddled by the iPod's format issues, and every review of the Zune really made it sound like a stinker. Only getting to listen to a song someone transfers three times before having to pay for it? Not for me.
Sound quality is generally excellent, and the volume stays consistent over tracks. Shuffle can tend to stick to the same artists, which is a bit irritating when you only want to hear, say, three Pillows songs in a row instead of five. The video transfer is pretty good. I've got TV-N's subs of eps 32-44 and the Hibiki movie on my Zen, and while the subtitles are a little small, it's still readable. I did have to run them through the video converter so the Zen could read them, but I've had issues with programs like Vegas seeing TV-N's subs as well. However, the Zen does support the most formats of any MP3 player.
My main issues with the Zen so far is that it comes with a totally impractical carrying case (it's a drawstring bag), the proprietary connection cable setup, and the lack of software integration. All the programs are separate, so it's irritating to have to run from one to the other when it shouldn't be any trouble just to bundle them in one interface. Also, there's almost always a small pause when loading some screens, even when you don't have a large amount of files. (I have around 4,000 tracks on mine, so I tend to get at least 10-15 second lag when loading the artist, tracks, or album screens)
So I would certainly say get one, as I'm very satisfied with mine.