Lots of good calls out there. My only advice would be to stay away from the gimmicks (like that squealing hen). Get yourself a good box call and a few different good slates with different pitches. Learn how to master them. There are some good videos on the net from experts showing how to execute each type of call. Yeah you can call in stupid birds making awful sounds, but if you want to consistently call in turkeys and have the upper hand, you have to sound like a turkey. Mouth calls are the way to go in my opinion except on windy days, but they take some time to master.
Anything from Knight & Hale, Quaker Boy, HS, and Primos will be good. If you want to fork over more dough for some custom calls there are a lot of good custom call makers out there too. I've called in most of my birds with the Primos Old Glory slate, and HS mouth calls. I also use the Knight & Hale slate hammer, Knight and Hale box, and the HS Lil' Deuce with a Primos custom striker. All of those have a couple of birds under their belt.
So many options out there it will drive you crazy but once you find what works for you with turkeys, its best to stick with it. I suppose that can be said about any type of hunting. Good luck, turkey hunting is seriously awesome and addicting.