Red,

Check the label on the B pillar of the vehicle on the drivers side, with the drivers door open. You will notice the factor spec tire pressures. Specifically that the fronts are 2 psi higher than the rears. Follow that, but if you choose to run higher pressure, make sure that you always keep a 2 psi differential between the front and rear tires.

However, having a higher pressure than the factory will give you better mileage, guaranteed. I run 40 front and 38 rear. Some run even higher than that. It is safe for the tires and safe for the vehicle.

It has been said:
Hybrid drivers come in 3 flavors, greenie, techie and cheapie. Pick any 2.
2005 Prius, Melinium Silver over gray, package 5 (AI)