There are lots of considerations when purchasing gear: price, ease of servicing, perfect fit and comfort, etc. You've indicated that you want to go for gear that 'grows' with you, rather than buying an entry-level set of gear and upgrading it as your experience/diving needs grow. That's great - I wish I had done the same. For example, my first regulator featured a balanced first stage and an unbalanced second stage. The darn thing was near indestructable and worked fine on dives above 60-feet, but anything deeper was a pain in the proverbial. Plus, when I started assembling gear for cave training - something I would have never forseen when I was choosing my first set of gear - it became plain that my first choice of regulator simply wouldn't do.
The major brands you see advertised (which include but are not limited to) Aeris, Apeks, Aqualung, Cressi, DiveRite, Hollis, Mares, Oceanic, Poseidon, Scubapro, and Zeagle - all make safe, reliable equipment. Providing the gear is serviced properly and maintained correctly, your gear should last for years and work perfectly. Some of these manufacturers are more heavily tilted to the technical diving communities, and may have more firepower than you actually need.
People have very definate ideas about the manufacturers they favor. I do believe that some brands are better than others for certain things. For example, I think Cressi and Mares make wonderful masks and fins (the result of years of experience serving generations of Mediterannean freedivers!), but I am not a fan of their regulators or electronics (computers and the like). Other people are, though, and that's fine. I'm willing to bet your final gear configuration will be a mix and match of brands, as you find out what's best for you. For example, you may end up with a Bare wetsuit, a Scubapro reg, an Oceanic dive computer, a Cressi mask, and Aqualung fins. Whatever works!
Be sure to find gear that can be serviced without too much hassle. (For instance, Sweden's Poseidon makes amazing dive equipment, but their US presence, while improving, is not brilliant, rendering the annual service an ordeal.) Note that there's a lot of cross-over between brands, so if your dive shop can service an Oceanic regulator, it's safe to assume they can also handle Aeris and Hollis regs, for example.
Play around as much as you can. If your LDS will let you trial equipment before purchasing, that's fantastic. See if you can talk to as many divers as you can about their equipoment while diving - most folk love nattering about their equipment, and hardly need prompting to do so. Also never underestimate other divers' generosity...many times I've been on a diveboat, heard divers remarking on each other's gear, and hastily switching fins (or whatever) so the other party can try them out before deciding whether or not to purchase.
Please also don't look upon your first equipment purchase as the only gear you'll ever have (it would be nice, but it's seldom the way it works!) Chances are that sometime in your diving career, you'll become enamoured of someone else's mask, fins, regulator, or whatever, and make the purchase. I bet there's more than a handful of divers on this board that own more than one of each item...
