I vote the Creative honestly. Maybe it's my sudden anti-Apple attitude which requires that I hate everything popular, but I think the Zen Vision M is a good device.
It has a much better screen, radio features, and I think it looks cooler and, most importantly, not many people have them. Of course, if you actually use iTunes and its Music Store, then go with the iPod. But if you use anything else, or want higher quality movie-watching/picture-viewing and want to take advantage of the plethora of file formats that the Zen offers. I'd go with that.
And then tell me if it's good so I can get one.