If cost is no object, a wooden fence does look great -- until the little stinkers chew on it and climb through or over a time or two. (Don't laugh -- I've seen it.) Another thing to consider -- small horses are nearly hidden by a wooden fence. We positioned our house and its windows specifically to be able to see them, I'm not about to block our view. (Planting my new garden beds has been a challenge. I love monstrous, rambling old garden roses, but not in the way of seeing my kids!)
My choice is 2x4 no-climb with a hot wire top and bottom. You can buy it in black now, which looks rather nice, and you could use wooden posts or paint the t-posts black. I choose not to use electric by itself, but a top and bottom hot wire will keep your horses off of your fence.
We have talked about wooden posts instead of t-posts on the fenceline closest to the house, but if we do that there is no moving the fence, which we've done numerous times.