I had an extensive CD collection I had built over many years before I got my ipod. It took time, but I imported all of those into itunes and then my ipod. I have an external hard drive for my computer that I use to back up itunes, and other files, on occasion should I have a computer crash. I had one early in summer prior to having the external hard drive. Fortunately most of my songs were backed up on a DVD.
You can buy CDs directly from itunes, in most cases for less than from a CD store or even Wal-Mart. And if you just have to have a CD, you can burn that from itunes.
I agree that I don't listen to satellite radio that much with my ipod. I certainly have no need to listen to a CD, single or 6 disc changer. Some vehicles now have hard drives built in.
Only problem with that would be it isn't portable. My ipod will also plug into a dock for my home theater. Great system. I love my ipod.