Auto Action - although I am biased
Antares Magazine - it's free, it's online, and ummm...again biased
RACE Magazine - it's aimed at the Club Racer/Engineer though, and er.... yeah, biased
Used to subscribe to Motorsport E-News, but gave it up. While it was substantially cheaper than AA, I spent all of 5 mins flicking through it, where AA I will read cover to cover, so reading time for money it's better with AA (for me).
Autosport gets a view now and then, Speedcafe sometimes (although not religiously). I used to get F1 Racing, but found I was less and less absorbed in reading it, so have stopped.
Almost forgot, also reading The Racing Magazine