I was a subscriber to Creem and Circus when I was a teen in the 70's. It was pretty much the only way to stay current on what was happening and what releases were coming up. In a pinch I'd even buy Hit Parader. However those titles died a long time ago, so I really recommend some great magazines from the UK that you can pick up at Barnes & Noble. Classic Rock (don't be fooled by the title, it's not about the lame US radio format), Vive Le Rock and Planet Rock.
Cool! I used to read those myself, back in the 70s, and I know what you mean about being the only way to keep up back then.
I used to be a long time subscriber to Rolling Stone, back when it was great and would actually feel excited when each new issue arrived.
I used to subscribe to it as well.
How Music Magazines are Changing to Stay Alive