BBH-
It is me CA77, posting off Dad's computer.
I assume you are referring to Academic, not athletic....It's hard to say, partially because I am prejudiced toward Canyon.
Amarillo High might be on top, because its huge size allows it to offer programs the other schools can't, such as Latin. Athletically, it shines more in the programs favored by parents who can afford "club" sports, like soccer. It probably has the richest kids, so there is a reputation of being full of snobs.
I'd put Canyon High up there, too. It has a good acadmic reputation, and great parent support.
From here on, my prejudice shows: Randall and Tascosa are in the next tier, then Caprock and River Road, then PD at the bottom.
The wild cards are Bushland and Highland Park. Bushland is brand new, adding a class each year. I think they only have 9-11 this year, this year's juniors will be the first to graduate from there.
Bushland has grown because of a lot of new development. That probably means lots of well-off kids which usually=good academics.
Highland Park is smaller and not in a great part of town, but they have a great tax base (industrial) and thus have wonderful facilities.
Caprock, by the way, has a lot of new homes in their attendance area, and a lot of good programs. I think it is on the rise.
And in my count of high schools, I didn't even think of the private ones. There are probably 4-5. I can think of San Jacinto Christian Academy, Acension Academy, and there are probably more.