Based on suggestions from some other PT forums in the past I replaced my original tires with Sumitomo HTR+ in 225/50-16 on the stock 7" wheels. I was so impressed with the ride, handling and wear that when I needed to replace tires again I bought the same ones. The best part of them is that they are quite wide and still fit comfortably in the wheel wells. You can read the reviews at tirerack.com.
I replaced the OEM Goodyear's with the Bridgestone Potenza Grid's and had to take them off after 5000 miles as they were unbearably noisy. ( Want to buy a set real cheap ? ) I replaced the Bridgestones with Michelin Pilot Exalto A/S and they're quiet, handle much better than the original Goodyears and they're smooth as velvet.