This is a cool thread! I mostly trail ride. Personally I don't find breeches very comfortable as they ride up on me or cut into my fat too much to be comfortable. I do have a pair that are comfortable when I'm at my preferred weight, they are cavallo's and were quite expensive. That being said, I still much prefer leggings/yoga tights as they don't ride up, are thin and light, and super comfy. I haven't had an issue with my tights wearing out prematurely but i do recommend either chaps or high boots, because otherwise the lower legs will get rubbed to pieces.
Boots wise, I have long rubber boots, my show boots, and my ariat terrain boots. I wear my ariat terrain boots mostly as they are so comfy and great when I need to lead a horse etc. They are pretty pricey though!