It's funny, I have Pink Floyd, the Beatles, Stevie Wonder, etc. on my iPod along with Coldplay, Green Day, etc., and the old stuff doesn't pale at all next to the new stuff, in fact just the opposite.
All that aside, I realized what we need to have happen to solve this volume wars problem. We need stereo manufacturers to build units where you set your volume where you want it, then the unit automatically adjusts the volume based on the detected RMS levels of the currently playing program material. Not unlike the car stereos that turn up the music when your vehicle speed increases to compensate for road noise.