Don't hunt, but do reload for all three cartridges and own maybe 9 rifles with them. Some of my favorite cartridges to shoot at range. All shoot quite well in my rifles.
I'd go with the 7x57 for your hunting needs. Also, since your action was probably chambered originally in 7x57, I'd eliminate the 6.5x55 just to avoid any possible feed problems using this round. Wouldn't be any potential feed problems with a 257R since its just a necked down 7x57.