I would highly recommend the iPod for several reasons:
1) Size and Weight, the new iPods are TINY, even making the 2nd gen ones look bulky in comparison, I just clip it to my shorts when I go biking, and I harly notice it's there.
2) Ease of use, it's a dream. People seem to miss the power of smart playlists. I am kind anal about my ID3 tags, even adding the Style info from allmusiguide.com in the comments field, but it lets you make some cool playlists. When you have 10,000 MP3s, it can be a real B$tch to keep everything in order.
3) Sound Quality. I have ER-6's and I usually listen to them at about 1/4 volume, and they're plenty loud, granted, 20db of sound isolation helps that out. Even the headphones it comes with don't sound tooo bad, unfortunately, they're huge and pretty uncomfortable.
4) Durability!!! (and 1 year warranty) I don't abuse my beloved iPod, but I dno't exactly treat it with kid gloves either. I take it mountain biking almost every day for 2-3 hours simply clipped to my belt in the case it comes with. I'd highly recommend gettnig at least the 15 gb model so you get the case, dock and remote. The case it comes with protects it from a lot, esp. scratches.
Honestly folks, quit whining about fingerprints, for christ's sake. the iPod is all but indestructable, I've read stories of people putting it through the wash and driving it over with their car and it still works afterwards. And no moving parts is huge. There's hardly anywhere for it to even get dirty. Like I said, i take it biking, and it's really dirty on a trail, but a quick wipe down on my t-shirt and it's nice and clean, nothing is messed up, Although keeping the plug in the dock connector might not be a bad idea.
5) Battery life. I guess quite a few of the other players have, some significantly, longer battery life, but here's my experience. I listen to it for probably 6 horus at work, and then 2-3 while biking afterwards, and it has never died on me yet. And the fact that you can charge it with the dock and firewire cable is HUGE not having to worry about batteries and $hit. I just plop it in the dock when i get home from work, it updates some of the random playlists I have, and I snag it in the morning, all ready to go.
6) And then there's always CAPACITY!!! I have the 30 gb which is a dream, and while I honestly which I could fit ALL my (60 gb or so) music on it, I think i'll live with 30, and the smart playlists make it a piece of cake to manage that much music. The fact that it keeps track of last played, playcount, rating, etc. lets you make sure you get to hear ALL your music when you want it.
Oh, and I almost forgot
7) All that extra stuff: Games, address book, calendar, news, weather, movies, directions, lyrics... I'd appreciate it if someone would let me know if the other players allow you to use this kinda stuff, but they're really handy. I have ALL my address book info and calendars on my iPod synced through iSync, but you can do it through Outlook or anythign else that supports vCards. And with Pod2Go I get movie times, news, stock quotes, and the most useful has been driving directions. and iLyric lets you download all the lyrics to your music library onto your iPod, which is tons of fun. Not to mention the fact that people are all like "wow, you have the movie times on your iPod?" They just sync every night, and they've come in handy more than once.
Anyway...that's my $.02 Good luck with your decision.
AND, you can get the iPod today
! and you'll not regret it.