I'm partial to the BMW and Infiniti since I have the most seat time in them. G37 will be the cheapest of this list and I absolutely LOVED my G35 but sold it when I got in to motorcycles because it just sat in my garage unused.
Cost of ownership / modding is exponentially higher than a motorcycle. It was one of the reasons I got out of cars and in to motorcycles a decade ago
If you're not a car guy already, I don't think a car is going to do it for you
See, I'm not the only one that can't be woo'd by a C6
My buddy has one, I was pretty excited when he got it and first time I drove it I was kind of surprised it was less exciting than I expected. Was fun as hell in the snow though
I'm with Tim