Here's a thought experiment for you all:

If a new mining technology comes along that provides the same MHash/s performance with 1/50th of the power consumption of the current state of the art, would everyone switch to this new mining technology? Also, assume that this new technology fits into the same approximate physical space as a similarly fast old-school mining rig, and that the cost is about the same per MHash/s.

A 5970 consuming 300W at full load is doing about 2MHash/s/W. The cost of the electricity at $0.10/kWh for this device is about $0.72/day.

If some new device comes along that consumes 6W (i.e. 1/50th), then the cost of electricity for this same quantum of mining falls to $0.014/day.

Annualized, the savings from the low power device would be $257, or roughly 1/3 the capital cost of the 5970.

Would this be enough to cause people to switch en masse to this hypothetical new mining technology?