Welcome to the world of diving!
Like most other products, there are many different brands of scuba equipment as well as individuals who are very loyal proponents of their favorite brand(s). And like other products, there are well-known major brand names as well as less established off-brands. Most people stick to the major brand names. I'm not convinced that one major brand is necessarily inherently superior to any other, though sometimes a particular model offers superior features over a competitor's model. What usually happens is that people will buy the type of gear that is sold at the nearest dive shop because that is where you bring it for service, and dive shops typically only service the brands that they sell.
Masks & fins - Aqualung, Atomic, Mares, Cressi-sub, SeaQuest, ScubaPro all manufacturer quality dive masks & fins. With masks brand is not as important as fit, a well-fitting mask is essential to an enjoyable dive. Whatever brand & style fits you the best is the one you should go with.
With fins, fit as well as the style of fin is important. The fin may have a solid blade, be split in the middle, have hinges, or have various other vents and channels intended to improve efficiency (or at least the perception of more efficiency). The brand probably isn't that important, though some brands specialize in certain types of fins (for example, with Atomic the split fin design is popular while Mares specializes in pivoting/hinged blades). Fin selection comes down to personal preference, but without trying different fins it will be hard to compare. In general, I suggest listening to what the dive shop recommendations are and then select something that seems affordable.
Snorkel - whatever is at the dive shop should be fine. Get something fairly basic, chances are you won't be using your snorkel that often (with scuba) after you are certified.
Regulators - the two most common brands I see divers use are Aqualung/Apeks and ScubaPro, along with the occasional Atomic, Sherwood, Mares or Cressi. When it comes to regulators I would recommend buying the highest performing regulator you can afford, regardless of the brand (with the awareness that higher price does not necessarily equal higher performance). Again, you'll want to go with whatever brand the shop sells/services.
BCs - major brands are Aqualung/SeaQuest and ScubaPro, along with Zeagle, Mares, and Cressi. Most brands offer BCs with similar features, so whatever brand your dive shop has is probably fine. Today's BCs will either be jacket style or back-inflate, and which you choose is personal preference (again, you will need to try each style to know). Comfortable fit, easy to use controls, and (in my opinion) multiple D-rings are the things to look for.
Computers - major brands are Suunto (Aqualung), Aeris / Oceanic (Pelagic), Uwatec (ScubaPro) along with Mares, Genesis, Cressi... Computers have a wide range of features along with an equally wide range of prices. I don't think one brand is necessarily better than another, but they do tend to use differing degrees of conservatism when it comes to their decompression algorithms. A liberal algorithm will allow longer bottom times with less of a safety factor, while a conservative algorithm will allow shorter bottom times with more of a safety factor. It is up to the individual to make the trade-off of dive time vs the additonal risk of DCS. I use Aeris, which is a pretty liberal computer. Suunto & Mares, on the other hand, use a notoriously conservative algorithm. I think Uwatec is somewhere in between.
Wetsuits - lots & lots of different brands: Aqualung, ScubaPro, Deep See, Henderson, Bare, Mares, Oneill, Harveys, and more. Wetsuit type and thickness is dependent upon several things, such as the water temperature, the amount of time you spend in the water, and your personal tolerance to cold. Proper fit is extremely important when it comes to wetsuits, far more so than brand (in my opinion). In warm water, say 80 F and above most divers will wear a 3mm full wetsuit (called a jumpsuit or steamer) though some may be comfortable in just a swimsuit or dive skin, others may be fine in a shorty, and others may add a hood or hooded vest and/or move up to a 4 or 5mm suit. In 65-75 degree water 5mm becomes more common, and may include a hood or hooded vest or possibly a move up to 7mm. A lot of it depends on you...I would suggest that you err on the side of warmth as it's a lot easier to cool off in the water than it is to warm up.
Good luck with your training and your future career!