Lightweight mini ipod recommendations

[EdwardGein]

I'm looking to replace my portable CD player with a mini ipod just for jogging- I need something less bulky, lightweight, with rechargable batteries that won't skip when I jog for at least 25 minutes or so. I'm planning to use my regular CD tracks and convert them to either wave or wma files as I don't want to lose quality which from what I'm reading here, you do if you convert to mp3 files. If I'm only planning to use this for jogging & wearing earphones/headphones whatever you call these things, would the difference between the CD recordings and the mp3 recordings not be noticable in that scenario?

Anyway, would appreciate any recommendations for both the ipod & earphones/headphones as my primary concern is comfort & to make these things as light as possible. As far as space is concerned , anything between 1-4gb is more than fine for my purposes. Anyone know where to get these used? Any help appreciated.