A wav file is lossless, and only very slightly larger in file-size than the audio tracks on the CD. A CD full of music is around 700MB, the wav files you rip from it will come in at just under 800MB.
CD encoding is 44.1kHz
However, you can't tag wav files like you can mp3s, and manually tagging when you do get around to encoding them as mp3 will be a pain. mp3 at highest quality setting (320kbps) is extremely hard to tell from a wav or CD, unless you have really high-end audio equipment.
Or you could create the iso image to your hard drive, if you only wish to store them (rather than have easy access to the audio files on your computer.)
You'll have to allow 700MB for each CD though, so you'll need a whole lot of disc space to archive everything without any compression.
You're right, if you choose wav you can't just burn as a data disc. Import the wavs into your CD burning program as an audio project before first.