My favorite is Garden Gate for diversity, readability, applicable info, over-all presentation and NO ADVERTISING. I've subscribed for a few years and also purchased their entire bound library of back issues from Day 1.
I also love Backyard Gardening for a friendly, easy going--"feels like it was written by real gardeners" presentation.
And while I also have a subscription to Horticulture, it is my third choice. Presentation is a bit more upscale which is nice but that is countered by too much advertising for my taste and not enough applicable info for my zone. While I enjoy it when it arrives, this is the only one of the three I won't renew when it expires.
Magazines, just like gardens...different strokes for different folks...
Single most important book I have read in years. It has totally changed my approach to gardening, and my outlook on the state of the world. I still haven't implemented everything I learned in the book.. but I would rank this book as being as important as, Silent Spring by Rachel Carson.. I can't express enough how much hope this book gives me about the future of the planet.. if people just listen.
I feel kinda bad posting this here, but even though its a catalog its encyclopedic in its scope.. and I often turn to it first when I run across plants I don't know.. besides its my bathroom reading material for most of the winter.
For magazines, I like "The English Garden" best. It has beautiful pictures of well established gardens, and each article contains a few tips from the owners and/or head gardener. A little grand, but real pretty to look at - everything from formal to the quintessential cottage gardens that the English are famous for. I like looking to see what I might be able to incorporate on a much smaller scale.
For books, I love Tasha Tudor's Garden - written by Tovah Martin with photos by Richard Brown. Tovah narrates a story about a stoic, eccentric Yankee octogenarian thru the seasons in her garden in rural Vermont. Great story, beautiful photographs. Tasha Tudor is known for her artwork for childrens books and her gardens.
They both sounds great. I'll check them out. My latest favorite is Creating a Perennial Garden by Joan Severa. Very down to earth and some good hints...Like I didn't know that you really don't have to work compost into the soil, you can just plop it on the surface around the plants and the worms will do all the hard work...that's saved me a lot of work.
I like Garden Gate and Gardener's World--the second is put out by the BBC, and you can't always translate zones and plants, but it has many projects and ideas and information--adds are mostly toward the back
Garden's Illustrated is another good one if you like to look at finished gardens-it also has good writing
I am am reading a collection of essays by Elizabeth Lawrence right now--I really like it