Old houses with tall ceilings and dark halls practically beg for more light fixtures than you'd think reasonable, and I've never once regretted adding a few. Rental apartments with low ceilings and a landlord who won't let you touch the wiring need to think a little harder, not because lighting won't help, but because the wrong fixture in a seven foot room makes the whole place feel like it's wearing a hat two sizes too big.
Finish matters more than style, in my experience. Aged brass and bronze forgive almost everything, they don't show fingerprints, they don't show dust the way a bright chrome does, and they only get better looking as the years go on. Black fixtures are having a long moment and I understand why, they disappear into a dark hallway and read as iron even when they're not, but they show every smudge if you've got kids or a dog that likes to greet people at the door. Gold finishes I'm pickier about. The warm, slightly worn gold looks like it's been in the family, the bright polished gold looks like it's trying to convince you of something.
Bedrooms want lower light and warmer bulbs, obviously, but the fixture itself can take more personality there than almost anywhere else in the house, since nobody's reading a contract by it. Hallways and stairwells are where wall lights do their best work, they keep the floor clear and they make a narrow space feel considered instead of just lit. Dining rooms are the one room where I'll tell you to spend more and go a size up from what feels sensible, because a fixture that's too small over a table just looks apologetic, hanging there like it wishes it were somewhere else.
Where it goes wrong is mixing too many finishes in one line of sight. A gold chandelier over a black and chrome dining set is the kind of thing that looks fine in isolation and wrong the second you stand in the doorway. And very ornate metal work, the kind with a lot of scrollwork and detail, struggles in a small modern room with clean lines, it ends up looking like a guest who wasn't quite invited.
What I like best is what happens after a year or two of ordinary use. The brass dulls at the edges where hands reach past it, the black picks up a little warmth under certain bulbs, and the whole fixture stops looking like something you bought and starts looking like something that was simply always there.