Lots of opinions and preferences. The car manufacturers use the tire pressure as a part of the suspension to keep the ride cushy, so recommend lower pressures. The tire manufacturers give you the safe cool tire pressure limits on the tire; don't exceed that. If the car is aligned properly and the tires balanced, the tires should wear evenly. If you are running too low a pressure, you'll see wear on the inside and outside of the tread. If you are running too high a pressure, you'll see center tread wear. Higher pressures give you better fuel milage. And most cars have a "highway recommended pressure" several lbs higher since you'll be driving on a relative smoother surface than the day to day surfaces most of us drive on. The highway partol officers usually run around 40 lbs for handling purposes. You need to consider the car weight as well. We run Michelin Sport Pilots on our LS430 and Buick Reatta and run about 37 lbs all around with good even tire wear. But both cars weigh in at 3800 to 4200 lbs.