I had a Doh! moment last night. My daughter has an iPod Nano. I have a Sandisk Sansa e280. So I've been ripping CD's in both itunes and Windows Media Player. Their standard ripping codec is AAC and WMA respectively. The Doh! moment came when I realized that both players also support the mp3 codec. So by ripping it in mp3 populates both itunes and Window's Media Player. Now I can reduce my music memory in the hard drive by half. That's for CD's you already own.
So, to buy downloaded music, it is also better to buy from Amazon MP3 or Walmart Music Download site where they sell it in MP3 format. This will allow you to play music in iPod and non Apple brands. iTunes only sells it in AAC codec so it will only play on their iPod device and a few AAC supported devices.
I guess I'll be deleting my CD collection and re-ripping them all in MP3 at 256 bit rate this weekend while my running friends run Hog's Hunt.