best tire pressure for 2007 toyota camry

ALWAYS follow the tire pressure recommendation listed on the tire placard on the drivers door jam. The tire maximum pressure is just that -- the maximum it can take. A variety of factors lead the vehicle manufacturer to specify proper air pressure for the tires on every vehicle.

Dave's answer is spot on. Follow the manufacturers recommended psi! The only thing I have to add is that 30 psi is what it should be at COLD. Warmer weather and driving times will cause your pressures to rise, sometimes by quite a bit. So don't think "well, 44 is max so I'll just set it at 40", because it will exceed your max and become unsafe to drive.