It's not the gear you use but the results you produce and knowing how to get the best out of each person, each location, each situation, and whatever equipment you have.
Having said that, I use a variety of equipment for different styles, effects and situations. I mostly use professional cameras and lenses by Canon, which are simply the best available.
Sometimes clients laugh a little after seeing the large, high-end cameras I use and then see me swap them for something much smaller and specialist. They are always amazed and thrilled however, at the results I get from them.
Let me give you an example.
I once took photos at a wedding with the often joked about "Box Brownie" camera. It was my grandmother's camera, I had it cleaned up and I did tests with it, and then used it to take a series of shots at a very old-styled and traditional wedding I was hired to photograph. The shots I did with this camera were specifically set up for the effect I was after, but often duplicated on modern cameras as well.
The couple loved the results, and had seven of the eight pictures I took on the Box Brownie as enlargements in their wedding album.