Unfortunately OP, everyone is right.... You're going to get a lot of people angry that you want to breed instead of buy one. Just PLEASE make sure the mare has good conformation and the stud, too. (I just asked about my own mare's confo - she is certainly not breeding stock.)
You'll get a ton of people most likely who don't believe in breeding unless the horse has proven itself in the ring / won X amount of shows or whatnot. Myself, I think that if you're not going to breed the horse for showing, that doesn't particularly matter.
Now, I'm going to get some hate for this I think, but I am also of the thought that winning in the show ring isn't genetic - Good conformation, the right build for the particular show skill, which is key in showing, is. (Also, good training.) Your horse could have won 100 medals, and so could daddy - but that won't mean the foal will at all. If they pass on their good conformation and you're a good trainer, now, that's what makes the difference. I don't believe a horse has to prove itself in the ring to be breeding worthy - as long as both animals have the proper build and the foal will have proper training, it can be wonderful in the show ring whether or not the parents have won 40 medals.
Now, I don't think that applies if your horse is registered with good bloodlines (As obviously you would want to keep those) and showing is a big part of what makes bloodlines 'good.' Or, if you're planning on selling anytime - show history adds value. As MysterySparrow said, you may have to sell in the future or unforseen circumstances. But if your just breeding a horse for your own pleasure, not as much. Even if you do plan on showing - I think that as long as the horse has the build and gets the training they will have as much potential as your neighbors horse with the same build and training, but with show history in the bloodlines. (Sorry, I'm not explaining this very well.)
To put it short: Make sure both horses are well put together before making the decision. Please think about adopting if the horse has any conformation flaws. My own mare, while I would love a baby of hers, has bad legs, and therefore I will not breed her. Instead I plan on adopting one. While I won't 'be there from day 1,' I will be saving a horse that might not have otherwise had a chance.