What cd player/stereo system will fit nicely in a '66 coupe?

Check out almost any Mustang mail order store (NPD or Virginia Classic). They have several different makes, grades and features. Speaker locations are: in the existing speaker position - not recomended, cut holes in the door - also not recomended, replace the kick panels - good choice and a hardtop had the capability of some good speakers in package tray.
Jim

Check out Mustangs Plus (http://www.mustangsplus.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=MPFMP&Category_Code=rdo) if you want a more classic look, or if you don't checkout crutchfield.com

It is my understanding that no cd player will fit in the existing dash cutout......

You can get a stereo with CD controls, but you would have to mount a CD Changer somewhere else in the car ie. trunk.

BTW: I tried listening to the radio in my Mustang, but couldn't get into it, I would rather hear my engine and exhaust. I also found listening to music was more distracting in my classic than in my other cars.

yeah unless you want to hack the metal dash up then you have to either get a remote cd changer or do like alot of the guys and run a stock radio in the dash and hide one in the glove box. etc theres also a new am/fm reproduction out that has mps inputs and rca out put for subs etc