Another vote for the single action
vaquero /blackhawk, in either 44 or 45, but i would say 44 if you don't reload.
That being said, the 357 is a great round, and will do 99.999% of anything you may need, as our esteeemed peers have stated.
If your buddy also has a 357, and you believe he can hit anything, than you should be fine with one of your own, 2 can do a lot of damage.
Buy what you are going to be the most comfortable carrying and shooting.