I don't really like the Mazda 6. If I were to get a 6 I would only get the MAZDASPEED6 which is around 30k..way out of my price range.
I like the 3 because it's sportier (and I like the three cylinders with the displays, one of the only cars I have seen with this feature). The 3s is actually the same hp as the base mazda 6 so the 3 is even faster because it's a lot lighter and more compact. Only the V6 mazda 6 or speed6 would be faster, both out of my price range anyway.
The car I REALLY like is the RX8...my (reasonable) dream car right now.
My all time dream cars are either the F430 or Maserati Coupe