The 2011 Porsche 911 Turbo S (530 HP, all-wheel drive, 7-speed double clutch "automated manual" transmission) recorded 0 to 60 times of 2.7 seconds when tested by Car and Driver and 2.6 seconds in the hands of Motor Trend. That 2.6 seconds tied it for fastest car in the world with the $1,500,000 Bugatti Veyron 16.4 Super Sport. Faster than any Ferrari, Lamborghini, Jaguar, Maseratti, etc. EVER built. Nah, not a fast car. The price for the 2011 Porsche 911 Turbo S - $161,000.
The brand new 2014 911 Turbo S sports 560 HP and adds all-wheel steering, active aerodynamic elements, regenerative brakes, a 4 inch longer wheelbase (the car grew only 2 inches longer), and options to improve fuel economy such as engine on-off technology usually found on hybrids. The price for the newer version is $180,000. Ferraris start at about $220,000. Nah, not a bargain either. And the Porsche gets better fuel economy than any of the other cars I enumerated.
Did I mention that the older, 2011, version kicks the 638 HP Corvette ZR1's 0 to 60, 0 to 100, quarter mile, and 0 to 140 mph times? But then, the top speed of that Porsche is a mere 197 mph compared to the Corvette's 205.
Where does Porsche fit in? It's the stealth and luxury super car - stealth because people have heard opinions and not the facts. Do you want me to tell you about the track monster Porsche, the 2011 620 HP 911 GT2 RS? Porsche hasn't announced a newer GT2 RS - yet.
One more: every year Car and Driver has a new car test of about 20 models they run on the VIR, Virginia International Raceway. In 2011 the cars came in this way (time around the track): Corvette ZR1 first, Nissan GT-R second, Porsche Panamera Turbo third, Boss 302 Mustang Laguna Seca Edition fourth, and Porsche Cayman R fifth. The Panamera is a four-door luxury GT saloon weighing 4,600 pounds and offering reclining bucket seats in the rear. There were no actual Porsche 911s in the contest.
ADDED: Several Answerers mentioned the 887 HP Porsche 918 Spider hypercar, but no one noted that it is a HYBRID sporting a 602 HP mid engine V8 with two electric motors making the balance of the power. It can limp home in electric only mode (if you call 285 electric HP "limping") if you run out of gasoline.