I'm a charter subscriber to Keyboard, so I pretty much stick with it out of loyalty. It has changed formats recently and is trying to reach out to older players (+30) and have even posted some arranger ads and reviews.
Used to subscribe to Electronic Musician, but its content doesn't interest me anymore.
The British Keyboard magazine is really pretty damn good, but way too expensive here in the States.
I like to get catalogs, especially Sweetwater, Sam Ash, Musicians Friend and B&H Photo. That helps me keep up with products and prices. And of course the internet is always packed with info. Try
www.sonicstate.com