Fast Company is great because they usually profile 5 folks per issue around some theme. Mostly senior manager to director level folks so you get a better insight into the working of companies. Also a really nicely designed mag.

The Inc. 500 is useful in that they publish revenue numbers of companies in a wide variety of industries. I've found it very useful when assembling presentations of comps.

Also, you can get subscriptions to both magazines for free ($5 max) with various offers online.