the one you feel most comfortable using, and which takes the lenses that you can a) afford, b)give the style of image you are after
You need to decide if you want SLR, range finder, scale focusing?
Are you ok with relatively modern optics with their sharp, contrasty appearance or would you prefer older, uncoated, less contrasty lenses?
Depending on what reportage you are shooting would you be heartbroken if the camera was destroyed i.e. don't use your grandads camera that is your only link to him to cover a riot
You can go down the motordrive and massive SLR shutter sound for maximum impact, or the silky, quiet sounds of a contax rangefinder with classic zeiss lenses.
I would suggest choice of film, developer, shutter speed and lighting are of greater importance than camera choice. In the end you just need to be comfortable enough to use the camera, and able to quickly change settings to react to events.
I like using my Leica with a 28mm f/2 for what its worth though