wow... you should never fill your tires up to the max.
most sedans and compact cars out there are set between 30 to 32 psi. Always check your tires when it's cold. After driving the car for a few miles, the tires warm up and expands due to heat, thus the psi goes up and it would be inaccurate to check your tires then.
Also depends on the area you are driving. For example, colder/wetter weather, lower PSI is better for more grip. The tire will be safe from wearing at as fast due to the mostiure or padding of rain or snow. Hotter/dryer, higher is better for MPG, ride, and wear/tear. But be aware of the max as PwTax stated, more so in hotter climates.
Ok, here is the deal. The sticker on the door is the tire pressure recommended by the manufacturer. That is the pressure they thought they got the best ride from. This is true for any car I know made today. Also true in all cases is that the maximum inflatable pressure for the tire is higher. The maximum inflatable tire pressure is the pressure where the tire manufacturer thinks you are going to blow/ruin the tire.
The reason that the front tires are inflated higher is because the front end weighs more (engine + tranny). On a RWD car, chances are you will see the number reversed.
It has been my experience that car mfg'ers tend to set the pressure of the tires too low. That may have been one of the reasons that Ford had all that Explorer trouble. The lower the tire pressure, the more of the rubber that meets the road. More rubber on the road equals more friction which easily translates to more heat. Heat the tire enough, and it will fail.
You need to understand what I am going to say next. I am my own idiot, and as a free American, I do what I please. If you choose to follow my lead, you have to admit that you are an idiot and are solely responsible for your own actions. That is, do not blame me for what happens to you if you actually decide to follow this thread.
I have played around a bit and found that +3psig over the mfg'ers recommended pressure has produced a better ride for me. A little more firmer and less roll. I have thought about playing with +5, but just have not had the time. It seems to have worked for other vehicles I have owned as well. Well, once an idiot always an idiot!