Slashdot has a discussion of the new 20 GB Rio Karma. It has a small form factor (2.7″x3.0″, that’s it in the middle), but is considerably thicker than the iPod. So, while the iPod is like a deck of cards, I guess this is like, what, a squarish hockey puck? It’s got some bells and whistles that the iPod doesn’t, but nothing extraordinary.
One advantage over many other Windows-based MP3 players is that it supports USB 2.0, a new standard which has only become common in PCs in 2003. USB 2.0 purports to be as fast or faster than Firewire, the excellent Apple cable standard. This is a bigger deal than you may think. I recently got another MP3 player for my Dad and set about loading my 3300 songs onto it. All told, it took like 12 hours to move that data on my USB 1.0 connection.
DarrenBarefoot.com 
Ack. Heresy. To suggest there is a replacement for the iPod ?!? – you can be banned from the cult for such statements.
Check here for a comparison between FireWire 800 and USB 2.0:
http://www.techtv.com/screensavers/supergeek/story/0,24330,3393571,00.html
Stick with FireWire is my advice.
You might need to consider a replacement when your iPod battery gives up the ghost. Apparently you need to pay Apple US$250 (plus shipping) to replace the battery, which seems to have a lifespan of 18months to 2 years or so; or you can buy a new one.
http://www.ipodsdirtysecret.com/ – has an embedded movie that is fairly well done, and plays the support call in which the ‘dirty secret’ is revealed.
actually, the iPod battery replacement service is $99, but you can buy do-it-yourself kits for under $60.
Is there a replacement battery for the Rio Karma?