Jaguar XKR by a margin of miles. Although the new isn't as staggeringly beautiful as the previous one, it is still to me the prettiest of the bunch here, I actually think the AMV8 is not that great looking, it looks somehow....I dunno, like it's trying too hard. The big brother DB9 just looks so much more natural.
And I also prefer the sound of supercharged V8 to the Astons normal one.
The biggest factor for me however, is the fact that the Jag is just so much more relaxing. I just couldn't drive the Aston everyday, it's too stressful. The M6 falls out of the competition basically because of it's stupid run flat tyres but it still isn't as stunning to look at as the 911 and the Jag.
Come to think of it, I actually dislike the "Baby Aston" very much. I agree, it IS a freezing cold car, as Jeremy said, but it just doesn't do anything for me. The DB9 however......my god I want one sooooooo badly.
I would take the Aston without a doubt. I sat in the new XKR (convertible) about a month ago, and i was impressed, it was comfy and the interior had some AM ques to the look. But a couple days later i was at the local Aston dealer and they had two V8s, and there was no competition. Who cares about practicality, i am not going to spend $100k on a two door car until i actually have a practical car (range rover, naturally) in my garage