For me it would have to be the World Champion 1915 Red Sox. The amount of unbelievable pitching talent alone makes this an easy one for me.
101 regular season wins.
Here is their pitching roster for those that don't already know:
George "Rube" Foster- No-hitter 1916- 2.36 ERA in a shortened career
Smoky Joe Wood- No-hitter 1911- 117 W, 57 L- 2.03 ERA career
Hubert Benjamin "Dutch" Leonard- No-hitters in 1916 and 1918 and the lowest modern ERA- 0.94 in 1914
Carl Mays- 208 wins, 2.92 ERA
Herb Pennock- 241 wins- HOF
Ernie Shore- 2.47 career ERA, 27 consecutive outs in unofficial perfect game in relief of Babe Ruth 1917
Babe Ruth, HOF HR slugger that just happened to be an unbelieveable pitcher too- 94 wins, 46 losses- Career 2.28 ERA, 2 World Series Rings AS A PITCHER!!