Go to your local university's bookstore and look at their magazine rack. If they have a good English department, they will have a wide variety of literary magazines to choose from. Furthermore, if you know a good English major, you might ask them to poke around their department for some--at my school there are always freebies from small presses laying around.
You'll find that most of the good stuff comes from small presses, and is therefore hard to find sometimes--this is not stuff you're going to get at Barnes and Noble.
Personally, for the balance of content, I really like the New Yorker and the Atlantic Monthly. The Paris Review is also an excellent literary magazine.
Oh, and don't forget to check the local university's library
as that's also a good place to look.