While you're in the PPL or early instr. phase, AOPA's Flight Training is a good general refresher.
Otherwise, Flying is decent, but a little too far removed from the flight training world (nearly every plane they profile costs at least $500,000).
I'd like to see a magazine all about the so-called lower rungs of pro pilot life: Pt. 135, smaller cargo ops, flight school news, CFIs, air ambulance, the regionals, etc. Maybe they could call it "Holding."