I pat mine, in the same way that I might pat a human friend on the shoulder. I've seen people praising horses who look like they're all out wailing on the horse's neck, that I'm not wild about, but a soft "good fella" or "howdy, Bud" pat is fine.
Then, it all comes down to what the horse is used to, and what the horse prefers. My first pony didn't like his face petted, even between the eyes, so we didn't pet him there. As years went by, he got more easygoing about his head, and eventually would rub his forehead on my shoulder, so we started petting his forehead, but he always hated his nose touched unless it was with the uber-fine bristled face brush. Scout, on the other hand, is "nosey" gently putting his nose in your face or hand and resting it there if you allow him, so, as long as he seems to enjoy it, we humor him and pet his face and ears.
I know people who think that if you hear your hand make contact with the horse, you have just physically injured them (this is a near quote from a friend of mine). Their horses always twitch their skin like a fly is bothering them when they get petted.
A stubborn horse walks behind you, an impatient one in front of you, but a noble companion walks beside you ~ Unknown