Great, good info--thanks. I suppose it's luck of the draw in determining whether I get a breeding pair. I always heard that I should get an odd number of angels, but I suppose that may not be necessary. Maybe I should just get two angels. If I get three, it increases my chances of a male/female pair substantially.....
Well.... that isn't the approach I'd take, personally.
Like most cichlid species, angels will often do best when there are more fish around to distribute territorial and aggressive behavior between. I'd probably start off with 5 or 6 in a 75gal tank, and then just see how things work out.
If you keep these same fish together (without adding or removing other Angels), you increase the chances that they will sort out their pecking order while young and small, and this may stay stable as they grow. It's sometimes possible to maintain breeding pairs with tankmates when they've been raised together. (No guarantees, but it *can* work out well sometimes.)
If you only start out with two of the same sex however, there most likely will end up a dominant and submissive fish. If the dominant fish turns out to have an aggressive streak, you're going to end up with only one angel in the tank sooner or later. Even if the submissive fish isn't killed outright, it's probably going to live a very bullied life. Submissive fish often end up stunted as dominant fish will hog food, or just keep their stress levels up so they often won't eat as well even if the dominant fish allows it. Unmated cichlid pairs don't always end up in this pattern, but it's pretty common.
So if you decide to go with angels, I'd personally either go with only one fish (not ideal as they really are schooling fish) or go with a decent sized group, keep your fingers crossed, and have a Plan B should the group not turn out compatible over the long run for whatever reason.