oh wow, what a crazy question.. I'm guessing if folks are willing to put their two cents in, you'll get answers from ALL over the board. I asked which was preferred (male or female) on another board and it was pretty much right down the middle.
I think you'll find all kinds of valid points for what breed excels well for what hunting type/location, etc.. and many breeds obviously do many very well.
Personally I looked up and down the sites and threads like this to make a decision on what I was looking for. I looked at what I wanted to hunt, and what I wanted at home too. I settled on an ESS - good, fun, upland hunter. I've heard good things about duck work with them too (which is something I would like to eventually do with her too). But the big thing for me was the package and family style. I know most bird dogs are good family dogs, but I needed something a bit smaller (medium size dog if you will). A large breed like a lab or GSP would not do. After all sorts of researching, reading, talking, learning, I was torn between a Brittany and a Springer. In the end, I went springer since a flusher suits my personality more than a pointer. Plus, my best buddy has a pointing breed, so figured we could have best of both worlds down the road.
another key I had to factor in, was how realistic was it to find the breed I was looking for. Here in California, boykins are damn near impossible to find. I have never seen one in person work, so I wasn't willing to gamble on a cross country dog just on a phone call. Not to say that can't be done and be very happy though.
anyway to you go, best of luck.