Practical Photography
Digital SLR Photography
Amateur Photography (every now and then)
Also and advocate of National Geographic.
None at all.
If you're just starting out then they are useful. Amateur Photographer and Digital Photo spring to mind as being the best in my view. But you get far better and more relevant info on here than any magazine. But after a while you'll notice that they do tend to repeat themselves quite regularly, almost by season. Not worth it at all once you've mastered the basics.