Before you spend money for a journal subscription, check out the online resources from your school's library. Through my school's library website, I had direct access to tons of nursing/medical journals with full text!
I never bought one (I'm in the last 2 months of nursing school). If I had bought one I would have bought one in something that interests me. One classmate bought a nursing journal centered around oncology nurses.
Get one that interests you. Might as well when you're a student and it's still cheap. Think about what you're gonna specialize in and maybe get a journal for nurses in that speciality. If you have no clue then get a general nursing journal.
For Christmas last year, my mom started my subscriptions to Nursing 2009, AJN, and Nursing Made Incredibly Easy. I read them all cover to cover the day they are delivered. They have all been assets, in my opinion.
I used my school's library of online journals but it is a complete disaster to navigate and search. To me, the money is well spent just to have a couple of extra resources.