I also have the XM channels with DirecTV and thanks to MusicLab, Deep Tracks, and The Loft I've discovered lots of new music that I otherwise would never have heard. It's great for background music or I'll turn it on in Zone 2 which is outside on the deck area to have some music going on out there. I used to burn a CD full of wma's and let it randomize but thanks to XM I don't have to fool with that.

As far as replacing CD's...never. I've bought more CD's since Direct picked up XM actually