Kind of depends what type of riding you are into. IMO sportrider is the best all around for sportbikes. I'm also a track junkie so I find Worldracing magazine to be awesome. If you're into stunting 2-wheel tuner is sweet. Then every so often I get superbike form Barnes and Noble from England. That is a awesome mag with great stuff but for $10 a pop can get expensive!

 

I find FastBikes to be a good magazine. Pricey, but they offer a lot of information, useful, trivial, but sometimes redundant. If you're a photograph/image type person, FastBikes is it. It's like the Maxim magazine for bikes.

My gf subscribed me to CycleWorld but I find the mag too bland. Most of the time, CW would end up in the trash after going through just so many pages. FB on the other hand, I can read it over and over and over. For some reason, there is always an article that I missed to read the first, second, and the third time.

If you're into track, Superbike and Roadracing World are pretty good as well.