How many times does this question need to be asked?
Pros use whatever tools get the job done for them. For some, it's Canon. For some it's Nikon. For some, it's a pinhole camera.
I don't know what the other pros shoot, but I know Ken Rockwell shoots a D40.
I think you misunderstood his question; he said "pro"
EDIT: ha... oops, I interpreted this as "what brand do most pros use" ...
What you're actually asking, then, is "Where is the money in professional photography?" I think that answer to that is mostly weddings, portraits (and variations of those) and photojournalism. I'm interested in pretty well anything that allows me to be freely artistic (ie.: no client telling me "I want this shot to look like this, with that in it, using so-and-so lighting, blah blah blah), other than weddings and portraits.
Before you are tempted to discover the answer to this, please choose one of the following options:
1. Kill yourself... or you'll wish you did after finding out who he is.
2. Add
127.0.0.1 kenrockwell.com to your hosts file. It will be the best thing you ever do for your photography.
Landscape is hard to get into because so many people shoot their own and are satisfied with that.
Landscape is difficult because it requires immense talent and has a very low success rate as a result.
but i also shoot live concerts...
That is also something I've gotten into recently, but is there a lot of money in that?
That is something I've ... not really gotten into. I'm always afraid that I won't be able to come up with any ideas.