It's not nearly as much the gun as it is the calling and the setup. Sure, you have to be able to hit what you shoot at, but learn to get them close and you don't have to worry as much about the gun.

That being said...

I'm not the best turkey hunter/caller in the world, so I like to be able to throw as much lead downrange as I can. I traded in my Mossberg 88 this year for a 535 turkey gun. I had a tom hang up at about 40 yards last spring, and with the setup I was shooting I knew that it would be a questionable shot. My new gun will smoke them at that range.

Look at the Remington 870's and Mossberg 500, 535, 835's. They have many fans. Just find a gun that's comfortable for you. They're all good guns. Try a couple 'turkey' chokes and different shells. Go in with some friends to buy several different loads and you can split the cost up (patterning turkey loads gets expensive). You'll find something that will pattern well in the 30-40 yard range.

good luck!
rw