My number one rule for buying a car is to drive them all and buy what you like.
I've driven everything from the M3 to Ferrari F430 and McLaren 12C. My favorite car is still my Aston - it has personality and you can feel it. It isn't the fastest thing around, but I can keep up with F430s and it always tickles my unmentionables every single time I drive it. To contrast that, the McLaren is numb. It's obscenely fast and really cool, but once you get used to the sensation of speed, it gets boring (happens to GTR owners all the time, I've got several friends that have cycled through those). I had the same feeling toward the 997 - excellent car, but boring to drive at anything under 8/10ths.
The M3 is a great car, very well balanced. The Corvette is great but the interior sucks and they're a dime a dozen. The NSX is and always will be a classic. Well cared-for NSXs will be collectors cars and skyrocket in value down the road (it's already starting in some ways).