Since I was taking the old smoke detector down anyways and (unlike the one in the kitchen) the smoke alarm isn't hardwired into the ceiling, I decided to move it. It used to be located here, right between the vent and the (broken) light fixture:
Though it was totally fine there, it didn't look as great as I knew it could. The vent/smoke detector/light fixture sight line was a little much for me. So, I took the smoke detector down, and was left with a small circle of popcorn ceiling that was never removed:
I removed the popcorn, patched up the ceiling, and repainted (ceiling is SW's Pure White). The smoke detector is now tucked right on the other side of the light fixture. Doesn't that look cleaner?
And I know that it works. And it is super easy to test and super easy to change the batteries. I feel safer and it looks better. I'm going to call this project a bit WIN.