Infiniti G35.

As much as I wanted to vote for the Mazdaspeed3 or the Honda Fit, I just couldn't. MS3 is just the already awesome Mazda3 with a new powertrain. And really... as awesome as the Honda Fit is, it's still a warmed over 5 year old car. That it's still great is more a testament to how well it was engineered 5 years ago.