Both the iRiver the Cowon are too expensive for me at the moment. Plus, I've heard that long filenames are a pain in the butt on iRiver, and the Cowon has suffered from remote problems, (which are huge problems when the remote contains the only LCD on the system).
My choices now are between a Creative Zen Xtra 40 gb and the Dell DJ 20. The Dell has longer battery life, (20 hours to 14), an in-line remote, seemingly better navigation, and a better backlight. The Creative has twice as much space, and a replaceable battery. Both cost the same. I would have gotten the Dell were it not for the fact that I already have around 12-15 gb of MP3's, and would like to also use the device to store videos, photoshop and dreamweaver files, and other PC content for the trip, as my laptop only has a 4 gb HD.
To the person who asked what I'll be doing with my CD's when gone, they'll be going into storage at my parents' place. That said, don't take that as sympathy for the record industry. Most of the CD's I've bought I've found out about the bands through Kazaa or Napster, (when it was still free), and come from independent bands who have been helped as a result of file-sharing services. Personally, I look to P2P networks as a way to destroy the power of the major record companies, who in creating popular music as an industry have largely destroyed it as an art.
Thanks for all the input, everyone. I'll be making my final decision tonight or tomorrow. I'll make sure to let you know how it goes.