We have 11 fire/smoke detectors that are all interconnected, one in each of the 5 bedrooms, one in each hallway (different sides of the house), 1 in the laundry, 1 in each office, 1 in the utility room and 1 in the main room of the lower level. On each level of the house there are also CO detectors, and on the lower level is a gas detector.
I don't remember the brand, but I do remember replacing them about 8 years ago (they were just over 10 years old). I found a fire safety discussion forum and followed a couple of threads that discussed callbacks and nuisance alarms; I based my replacement brand decision on that, and have had no problems with them. I suggest you do the same in order to get a good idea of what brands/models currently offer the best quality when you're ready to make the purchase.
They are all due to be replaced in 3-4 years, and I'll do the same research to determine which brands/models have the same low callback/no nuisance qualities. Since quality and models can change, basing a future decision on any current model is foolish.
In addition to the smoke/fire detectors, it's also a good idea to keep fire extinguishers located in strategic locations: we have one in the mud room just off the kitchen, one in a closet at each end of the main level of the house, one in the utility room, one in the laundry room, and one in a closet on the lower level. 2 in the attached garage and 3 out in the shop.