No. Some people do the hibernate thing and they say they can let it run a few days while the car is parked, but I don't feel comfertable doing that. I have the red lit power button and the griffen power mate that "breathes" blue. (very slow pulse). I think it would draw too much attention at night.
I just turn the screen off and pause the music. The computer doesn't draw much power. Maybe 60W total. Just the motherboard by itself only draws about 14W. Even though the inverter is a 300W, it will only draw what it needs to power whatever is plugged into it.
BTW. what's with the friggin' huge signature pic?