I can still believe that CDs cannot accurately record/reproduce the incredibly high overtones some instruments make

But microphones can't capture it, anyway. Still, it makes sense to use higher resolution (both bits per sample and samples per second) in the mastering phase to generate the best possible CD at the end.

If you really want higher quality, then the current buzz seems to be around super audio CDs (SACDs) and DVD-Audio. A friend of mine has all of this set up with a stereo system that costs as much as a good car (Piega speakers, some sort of new esoteric subwoofer, a Nakamichi amp, Sony SACD transport, and variously overpriced interconnects). The intersection of his tastes (classic rock, classical music) with mine left only one album I really knew well - Pink Floyd's Dark Side of the Moon. When they remastered it for 5-channel audio, they went out of their way to hit you from all sides. Time has the bells ringing everywhere. Likewise, Money has cash registers chinking at you front, back, and side. Very impressive with lots of fun bling-bling, but there's debate about the quality of the mastering. It certainly sounded good, but we didn't do an A/B test between this and the original CD mix.