Saltheart, why not set your computer to go into Standby Mode after being idle for a period of time?
Then, when you come back to the computer, a simple press of the spacebar and it should be ready to go in 10 seconds or less.
If you need a hand getting it setup, let me know... Or this might help:
http://www.genexe.com/?p=498
My understanding is that a computer in Standby mode uses less than 10Watts of electricity - upwards of a 70-80% savings (using a 500W PSU)
Threaded Mode