Here are the magazines that I currently subscribe to:
Grassroots Motorsports By far, this is my favorite car magazine - it's down to earth, full of project cars, and they understand things like slip angles, heel-toe-downshifting, autocrossing and HPDE's! Excellent magazine for those into autox, DE, club racing...etc.
Porscheforus This is the NNJR PCA region's monthly publication. Its great because it has good local content. Plus my mug is on page 2 every month! (I'm on our Board of Govs - track tech co-chair!)
Road & Track My source for info from the 'mainstream' auto industry. I work in the IT dept. for Mercedes Benz USA headquarters, and most of us at work are 'car guys,' so I need to keep up with what's going on with the competition. BTW: Road & Track, Car and Driver, Motortrend - they all pretty much cover the same thing, so just get one of them. I am considering switching to Automobile - I've bought some of their issues at the newstand - I like their writing and content better.
Excellence I used to love this magazine, but it's gotten to be too full of ads and not enough content, as stated above. Still a good source of info on all things Porsche.
Panorama Read some of the articles in it, but it is only a little better than Excellence.
-Z.