i generally don't have brand loyalty, but i've narrowed the car choices down to a new Nissan Altima coupe or a used Infiniti G35 coupe. Nissan/Infiniti just happens to have a nice selection of coupes that i feel comfortable in. fully decked out, the price ends up being a wash between the two. the Altima is smoother, quieter, great gas mileage. its also the 1st year for the coupe; being different is good. the main negative is i'd be paying the premium for purchasing it new. the Infiniti is sportier (also bumpier), has more power, and some status associated with it (i'm shallow). buying it slightly used, its already taken the major depreciation hit. its major negative is barely passable gas mileage and it takes premium gas. could go either way ...
Honda Accord coupe is out because its close to the Nissan Altima coupe, but i prefer how the Nissan handles/feels. Cadillac CTS is out because its options packages quickly add up to make it considerably more expensive (even with the family discount). if the coupe was out (not until next fall), then i'd consider going for the upsell.