It has been a long thread, but one point that has been mentioned only in passing (VMWares "top 5 reasons") is cutting the electricity consumption. Maybe this is obvious.
I recently consolidated 8 hardware servers to a single 1U Dell, which runs KVM virtualization. The power bill was cut to a fraction! Do the same on a bigger scale, and it will be a significant saving. Also it reflects on cooling costs. Good for the planet, too.
- Jussi