The Bishop Opening is quite religious.
Religious openings

I accept the Smitth-Morra and Blackmar-Diemer gambits religiously because of my firm belief that they can't be sound. In the case of the latter, this leads me into trouble often, but that is because I have never actually looked at its lines. But then I don't have to, because I have faith. I just need to believe harder.
Over the board I've played 1.d4 exclusively for about six years now, after finding out that my 1.d4 career TPR was 200 points higher than my 1.e4 career TPR. But recently I'm preparing to reintroduce 1.e4 (by playing chess.com online games with it).

Ever since I moved into the 1800's region I've stuck to the same openings whenever possible. My opening repertoire is pretty large (ie, I don't play the french against everything like so many people I Know :P)... so I still get lots of variety... but whenever possible I play the same openings (Benoni and Kings Gambit being my two most common lines I suppose).

I'm a one-horse pony, I play d4 and then it's usually QGA or a catalan, against d4 I play the Nimzo-indian, and I flounder about with the sicilian when faced with e4.

Actually these are the openings i am glued to:
White: Ruy Lopez
Black: French Defence (much to ih8sens liking!)
Ravi

Usually as black I'll play the Sicilian or an Indian, depending on White's first move, and usually 1. e4 as white. Never got used to 1. d4. Ever. Once in a great while I'll try the English or Reti, but not often.
As White, I nearly always play 1.d4 and get into some Queen's Gambit position, or 1.Nf3 if I feel like castling earlier. As Black, my favorite response to 1.e4 is 1...c6 (The Caro-Kann) and against 1.d4 I usually employ the Benoni Defense or the King's Indian.

My 1st move as white is always 1.e4, and my first move as black is always 1...Nf6 (The Dark Knight Opens).
As White I usually open with d4, playing the queen's gambit, but I'm thinking of experimenting with the RUy Lopez for some flavor and change. As black I'm experimenting with QGD vs Slav vs d4 and Sicilian vs Caro-Kann vs e4. If he opens with something else, I wing it.
Do you, whoever you are, have an opening that you religiously stick to or... not?
Answers on a postcard!
Be interseting to know though, do high raters always open with the same moves?