I use a creative Zen micro Photo. It's 8 Gb and I like the fact that there is many (and more to come) music services where you can buy and use. I have a subscription to Napster to go where you pay $10us or $15 Canadian monthly and you can download and listen to as much music as you want.
The Zen will play MP3, Wave and WMA files, I found the Zen to have a better sound (I bought both a ZEN and Ipod and compared sound with wave files of the music I like and found the Zen to be much more cleaner. )and the fact the model when I bought it came with an extra battery was a nice bonus.
Ipod has a lot of add-ons you can buy if you big for matching you Ipod slip cover with the shoes your wearing that day. I'm not a huge fan of how restrictive their Digital rights management are so that why I will not buy an Ipod or Sony product. -~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~-~
Of all the things I've lost I miss my mind the most.