The sicilian against higher rated opponents, and e5 against lower rated. That is what I've experienced when I open e4. Those are the most common against me.
What openings do you face as you rise through the ranks?

Many openings are popular across all levels, from what I've found -- the Sicilian and French defenses immediately leap to mind.
As you rise in rating, you'll see less of the gimmick openings, though. For instance, a 1.d4 player will see a fair number of Albin Countergambits at lower ratings, because it's easy to learn, forcing, and trappy. At higher levels, though, you'll almost never see it, because once your opponents are wise enough to avoid the traps, you're left with a poor position.
What you will see more of, though, is pure hypermodern openings -- the Grunfeld, Pirc, Alekhine's defense, etc. These are too difficult to defend as a beginner, but the subtle and unbalanced nature of these openings appeal to some experienced players.
I don't think there's a level below professional/high titled players where everyone plays the main lines. I might say there's less focus on forcing variations as you rise in the ranks, but there are plenty of perfectly playable side/uncommon variations that you'll continue to see those for a long time.

The most striking feature I've notice in OTB play, is that players under 2000 have a tendency to avoid complicated lines and go for simpler positions, or play stereotyped set-ups. When you go higher (2000-2300), you see more main lines and more complicated stuff (ie. more sicilians, semi-slav). And when I play people 2300+ (it's rare but it happens), then they prefer to play offbeat against me and get me out of the book early.
I read someone's comment that after getting out of the newbie stage of chess development, they seemed to face 1....e5 fairly rarely until they made it a little higher, when some opponents seemed to go back to it. Is that a common experience?
It also got me wondering about the openings, and whether some of them are more popular at some levels than others. I am guessing that the Center Counter is one of those openings you stop facing after a while. I'm thinking that certain obscure and tricky opening variations become popular as players become aware of them, but not to the degree that their opponents are going to know the theory too well. I've heard that the pawn grab in the Open Lopez is like that.
It is easy to find stats on the pros, but not on club players. What have you guys found to be the case? At what point do most players give in and play only theoretically approved mainlines?