Throw out the Mitzu Lancer first. IMO, Mitzu suck period. I've had too many friends with problems related to the Eclipse and Lancer. Another friend just bought the Endeavor, so I'll letcha know when their is a problem.
The BMW and Audi are not in the same class as the Mazda3. Who wouldn't want a BMW/Audi over any model of Mazda??
The 2005 Mustang is nice; however, it is a mustang after all. I know its more of the people that suck that drive mustangs then the actual car. Mustangs have always been horrid in winter weather. Have been a witness to many donuts on the road with mustangs.
Acura RSX is nice, fast, and not too bad a car.
For the $$, I'd select the Mazda 3 or RSX.