I currently have a 2 year old Creative Zen Jukebox (40 gb), and an iPod Nano (1 gb) (which was a gift). I like them both for different reasons.
I am an audiobook addict.
The Creative has a ton of room and I always have several books loaded on it. Plus it has a bookmark feature which lets me go back to where I was in a book after I've been listening to another one, or music. Plus it has a removable battery. I have an extra one so I can keep a charged one ready which is great when I travel.
The iPod I love for exercise. It's small, the controls are easy to use and it has great sound. The small capacity is a drawback, and if I'd been choosing I would have gotten a bigger one. I ended up buying a plug-in charger so I could take it with me on trips where I didn't have access to a computer. And while I like iTunes better than the Creative interface, I don't like that most of my audiobooks won't work on the iPod without a lot of manipulation. I get books from Audible.com which I can load on the iPod (when I have room), but the ones I download through the library need Windows Media.
I recently had trouble with my Creative, and I've been looking into getting a new one. The Vision M is what I've decided to replace the Jukebox with when I need to - unless of course it's months from one, at which time I'll be researching again.
If I were just doing music, or podcasts, I'd look more at a larger capacity iPod.
And for the record, I don't do any video on mine. Haven't really looked into it.