How long will it take to mine 1,000 Bitcoins at 3Ghps?

[ribuck]

So if you are planning to mine for an extended period of time, you should concentrate on Mhash/W

Yes I think you have nailed it. In the long run, miners with the lowest electricity cost per hash are always going to be profitable. Other miners will experience good and bad times.

[JeevesNZ]

So if you are planning to mine for an extended period of time, you should concentrate on Mhash/W

Yes I think you have nailed it. In the long run, miners with the lowest electricity cost per hash are always going to be profitable. Other miners will experience good and bad times.

...such as those who have managed to sneak their mining rig into work and not pay for the electricity