Mike,
I saw your tread on Mike Lavinge's systempost about the system rack... I can give you a few pointers.
The Grand Prix system racks are amazing. It is not just a rack but rather an isolation system. Each shelf is damped by shock-absorbers tuned to the weight of the component it supports. The posts can be filled with cromium-ore or sand. At the moment with your current setup vibration generated by the speakers (naturally) will be transmitted through the system cabinet and into the equipment. The can cause harmonic-smear, feedback distortion and a host of other problems. Youll definitly notice a difference if you place your CD/DVD machine, pre-amp, DAC and power-amps on a good isolation rack like a Grand Prix...
Best regards,
Dewald Visser