The gear you buy depends on a number of factors but I wouldn't get caught up in brands. Any of the more well known brands work pretty much just as well as one another if you keep them well maintained by the right people. Most people will tell you x brand is better than the next. Ask 100 people and you'll probably get 100 different answers as to why their gear is the best.
Buy soft gear (fins, mask, wetsuits) that is comfortable. This stuff is a must and is usually the stuff I won't go anywhere without.
Next buy hard gear (BCD, Regulator) depending on how much diving you are planning etc. If you are diving once a year on vacation I wouldn't buy this stuff. With servicing costs each year you're better off using rental gear. If you can't trust the dive companies rental gear you shouldn't be diving with them! If you are diving more often again get stuff that is comfortable for you. Some people like jacket style bcd's, some people like back inflation and others like the backplate and wing. Try some different stuff and then decide. What you like now may not be what you like a year from now but you can always change setups. For regulators get something suitable for cold water you may not be diving in it right now but you never know a cold water regulator can still be used in warm water but a warm water regulator may not work so well in cold water. Decide if you want entry level or high end. Personally I would choose something in between. But they all work some just breathe easier than others and supply more air if you need it.
If you want brands stuff like scubapro, zeagle, mares, aqualung, seaquest, aeris, apex etc are all good brands. Tusa also make great softgear.
Personally would support whatever one of your dive center stocks, that way you know they have qualified service technicians and spare parts.
Good Luck.
