Rich, since this IS a "debate" site, I will debate a little wicha'. IMHO the MP3 as long as recorded at 128 bps or higher is CD quality or higher. Sadly, many voices are recorded at about 48 bps, which gives it a mechanical computer sound.
New CD players are coming out all the time that will play MP3. It is unlikely the car player will; however, due to the date.
Our Christian radio plays strictly MP3's at 128 to 160 Mhz and I dare anybody to tell the difference between the music and CD music.
MP3's typically get a compression rate of about 10 to 1. In other words, 100 megabytes will convert to a 10 megabyte or lower, depending on bits per second of the compression rate. If you are not stereo, then you can cut it down even more.
ALL DVD players will play MP3's. They will show the menu on the television screen and you pick the ones you want to play.
If you buy a walk-man style CD player or any new CD player, you can pay a little more and it will play MP3's. The reason it cost more is that the MP3 ands for Motion Picture and they have to pay a fairly large royalty in order to put in the software to decode the MP3 format.
At Wal-Mart a typical "low-cost" CD player in walk-man format and head-phones is around $20 to $30. Whereas one that will also play MP3's will run $50 or higher. But, then again, look at the savings in disk space. This will also give you a good back-up of your CD's in case they get damaged. Record and compress the CD's on a computer with a CD recorder and put the originals where they are not exposed to light or wide-temperature ranges. Use your copied CD for carrying in the car.
You will pay enough for the CD's so you need to protect them and it is okay if you record a backup set for your OWN use.
Even if you cannot compress them, give them to someone with a computer and let them make a back-up set for you. At typically a quarter for a blank CD, it is a cheap way to protect your investment. Just remember that home recorded CD's scratch easier. Don't use a paper label either, they can gum up your player. Write on them with a permanent marker, the type used to identify clothing. (Of course, write on the top side that doesn't have the music on it.)