the reason your front tires look low is because that is where all the weight is. the engine and tranny weigh down the front of the car. reccomended tire pressures on the cars tire placard only apply to the EXACT size brand and speed rating of the vehicles OE tire. Any change to size, brand, type or speed rating of the tire will effect pressure settings.
Remember to check/set your pressures in the morning when they are cold. Yes driving to the gas station still warms them up enough to change pressure.
Set your pressures the way you like them, rotate your tires every 8-10000kms or every other oil change, and they will last alot longer.