Buying an mp3 player

I'm going to UCSC next year where I won't be permitted to drive a car, which means my wonderful Alpine deck will be useless. I'm taking my NAD/PSB system to my dorm/apartment and I'll probably be using my computer and my Marantz DVD player as sources in my room, but that still leaves all of the time I'll spend on my bike, the bus, and the train. I was about to purchase a new portable CD player to replace my recently deceased Disc Man when I starting thinking about MP3 players. After reading many reviews, I've narrowed it down to the ipod and the Creative Nomad Jukebox Zen Xtra. The 40 gig models of the ipod and the Zen cost $500 and $270 respectively, so I'm currently searching for any further information to base my decision upon. I've heard that the ipod battery life is less than four hours from a lot of people who use their ipods while running. The same people have also said that the batteries have died very quickly and that their ipods skip quite often. Has anyone else who uses an ipod while running had a similar experience? The size differences don't matter to me, but I am concerned with sound quality, battery quality/life/ease of replacement, potential to connect the player to my preamp, as well as to my car for next year when I regain my driving privileges.