Your correct vcore should be measured on CPU-Z UNDER LOAD. So anything that puts your cpu usage at 100% (folding, orthos, prime, etc)
Sorry, but seriously what i said is what should be used because that is the closest ESTIMATE of what the chip is actually getting. Vdroops are different on all boards so thats why it would be extremely inaccurate to post the voltage before droop. You dont know vdroop their board will have.
Since the 45nm CPU's are being killed due to excessive voltage, it is still a bad idea to set the vcore to be less than the recommended under load and not consider what it is at idle.