A comment on the Mazda 6 - I would not consider it to get good mileage. IRL, about 19/22 City/Hwy for the V6, and the I4 felt too underpowered (for the weight of the car) to be any better. Currently, I drive it with mileage in mind, when I get on it, low - mid teens. I get the best mileage of any Mazda6 owners I know; I have a friend just traded his in on a 5.4L F-150 - gets about the same mileage and can haul all his business equipment with him....
Other than that, great car.
Personally, I wouldn't consider any of the VW-sourced cars (Passat, Jetta, Audi A/S4) to be reliable in the Japanese sense of the word (they'll still probably get you from point A to point B well enough, but you may not be able to open the windows, use the A/C, radio, etc). Though I would buy an S4 for myself, they are not for everyone....