Suspend vs. Lock vs. Screen Off

[Jason Cawood]

I'm using the latest FDOM, I believe it's based on 2008.09.  My question is
what is the fundamental difference between pressing the power button to
cause the phone to suspend, pressing the aux button to make the phone lock
the screen and not pressing any buttons and letting the software timeout. 
Mainly, I'm interested in battery life and how each action reduces power
consumption.