I don't know how important it is to you to be able to use iTunes, but here is a list of compatible players:
http://docs.info.apple.com/article.html?artnum=93548 (Note: not sure how up to date this is - some of these are not new players)
With the Sansa, you should be able to connect the player to your Mac and drag and drop your music files (though see comments after article in last link below - apparently even that is not foolproof). You won't be able to use iTunes with a Sansa. iTunes and the older Nano Bill mentioned will be fine.
Also see this
SlashDot discussion of alternatives - including one I wasn't familiar with (Cowon). Also read the post from Minority (long post more than halfway down) about how he wishes he'd bought an iPod.
The integration with iTunes is wonderful, IMHO. Everyone in our household now has their own iPod, and I doubt I'd buy another brand of Mp3. iPods just work - the software is excellent, the interface easy to grasp etc. We've had the batteries replaced on both our older iPods (1st gen 4GB Nano and 40GB 4th gen) and it was worth doing.
You might want to read the comments at the end of this review of one of the Sansa lines (not sure which one you're looking at) - I'd say there were enough unhappy campers to warrant some concern:
http://www.engadget.com/2006/06/01/sandisk...sa-e260-review/Here as well, again in the comments section:
http://www.engadget.com/2007/10/23/sandisk...w-gets-unboxed/
