There are hundreds if not thousands of flashlight manufacturers in the United States and the rest of the world. Some brands are widely recognized by consumers. Other brands may not be widely recognized, but they are great flashlights.
When looking for a flashlight, you should consider performance, size, design, durability and price. You can get a flashlight for as little as a dollar or two (batteries included) that will work in a pinch. A cheap flashlight probably won't hold up over time, though.
At the other end of the spectrum, there are powerful, well engineered flashlights. These are the flashlights that are used by police, military and emergency workers. They can set you back $100 or more (for just one flashlight).
When shopping for a flashlight, the primary concern for most shoppers is the price. For most home use, buying a flashlight for $20 or less is usually just fine. For under $20, you can get a well built, durable flashlight that casts a bright light. Light is measured in lumens, so the more powerful flashlights will boast a higher lumens rating.
You should consider when you might be using your flashlight before you make a decision. Will you use it only for emergencies (such as power outages) or will you also use it outdoors (for camping, boating, etc.)? If you're going to keep a flashlight on your boat, look for one that's waterproof (and maybe one that can float).
Remember that high quality aluminum casing costs more than cheap plastic, but the trade-off is that the flashlight will last longer if it's made out of durable materials.
There are also different light sources to consider. The best flashlights use LED lamps to project bright light. They last a very long time and do not emit heat like bulb-based flashlights. They also use less energy than bulb-based flashlights.
How do you know which brand of flashlight works best? Chances are if you go to the store and buy a flashlight from Brinkman with an aluminum casing and halogen bulb, it will be about the same as a Rayovac flashlight with aluminum casing and halogen bulb. The main difference may be in the styling or color of the flashlights. Other popular brands include Coleman, Dorcy International, Maglite and Garrity. Reputation accounts for the popularity along with marketing and perceived value. Ultimately, your decision should probably come down to price and perceived quality.