Wherever the horse isn't being judged on their appearance, I.e. Barrel racing, showjumping... etc. or where there's a different standard of a "good" headset, like in saddleseat they tend to have their noses up in the air... as well as some breed shows.
Having said that, being on the vertical isn't just about looking pretty, it's also functional. Once a horse has a proper frame, that includes being on the vertical, but also a number of other things, it means they are round through their back therefore working through themselves.