How accurate do you want the power measurements to be.

Inductive pickup clamp type devices arnt very accurate as they dont know anything

about phase angle, so cant tell the differance between watts and VA, and they only work with

sinusoidal current waveforms, so will be inaccurate with loads with switchmode power supplies.

The only accurate way to measure power consumption, is to both measure the voltage and current

and compute the RMS value of both to obtain the power.

There are dedicated ICs available that do all you need, like this.

http://www.maximintegrated.com/datasheet/index.mvp/id/7080