Car&Driver is one of my favorites. I've been reading it since 1978 (when I was six years old!). I also like Practical Classics (British mag), F1, Mustang Monthly (since 1982!), and Road&Track. I used to love looking through the Hemmings Motor News.
As for Motor Trend, you only need to know one fact: Motor Trend's Car Of The Year 1983- Renault Alliance.