When doing my very first CD rip, I got quite different size files. EAC produced a 867 KB Wav file, while Cdex produced a 21,806 KB Wav file on my hard drive. These two Wav files both played back fine using Winamp. So I have no idea as to why the two file sizes are so different?

If both files played the complete track, it looks like you produced a compressed WAV with EAC. In EAC, enter F11 and make sure the Waveform tab shows “Internal WAV routines” for Wave format. This will produce a WAV file that is about 176kB for every second of music.