The only CDs I buy anymore are of 311. This is their most recent one (last summer, maybe) called Universal Pulse. It looks like a 3rd grade Trapper Keeper.
I, like others have mentioned, like having the physical CD as a backup should any of my electronic devices die. Occasionally I will buy songs on iTunes if I just want a "hot new single" or some other song I'd be embarrassed to own the CD of. Or, for example, when I watched Gentlemen Broncos and decided I needed the song "In The Year 2525" by Zager and Evans but didn't want to bother buying the entire soundtrack:
[ame="http://www.youtube.com/watch?v=izQB2-Kmiic"]Zager And Evans - In The Year 2525 - YouTube[/ame]
I have had good luck buying used CDs at Half Price Books in West Des Moines (near Fareway, across the street from Guitar Center). Their inventory seems to cycle quite a bit, and I find a lot of good CDs from the past decade and beyond. On my last visit I left with:
Interpol - Turn on the Bright Lights
The Shins - Chutes Too Narrow
Arcade Fire - Funeral
Spoon - Ga Ga Ga Ga Ga
All for $6-7. Never had any issues with unplayable discs from them. They also have quite a selection of vinyl, mostly older stuff.
Ames also has a nifty little record/coffee shop downtown called Vinyl Cafe. Just around the corner from the cupcake place, below street level.
For car music I rip all my discs to WMA Lossless, copy it to a 1TB USB Drive formatted to FAT32, and plug that into the USB port in our Ford Fusion. Microsoft Sync indexes everything so you can manually search for artist/album/song/genre using the radio controls or voice command. It'll also read the iTunes files that are not DRM protected (pretty much all iTunes files are free of that crap these days). I probably have at least 500 albums on there with plenty of room for more.