I just have to put my two cents in for the good old-fashioned big-boned, solid and sane Thoroughbred, and it's not only because I'm standing one at stud.
Throughbreds have a reputation among some people as being dificult and hot. I disagree. The most dangerous horses I've worked with have all been warmbloods and draft crosses. There is a stubborness and a chicken-heartedness in some of them (certainly not most) that I've rarely found in a Thoroughbred. Tb's certainly have a lightness and love of movement that worries some riders, but it's almost always a safer way of going on a cross-country course than a heavy horse who is indecisive about getting to the other side of a jump.
I don't really want to offend anyone, but why borrow blood from breeds that were developed to pull plows for a sport that is done mostly at the canter and gallop?