OK, i have a different take on this....
Ask the dive shop if you can try out the gear in one of their pools. If you are buying online, well, you are kind on your own there. Most reputable dive shops will be fine with you trying on the gear in one of the pools that they rent, so you can see which of your purchases is the most comfortable and the best for you. As for the whole streamlining thing...sorry, but the difference between a BP/W and a jacket style isn't enough to be significant, IMHO.
Regulators...heck, any regulator you buy these days will be more than adequate for a sport diver's needs. most will be adequate for even a techie's needs as well. In my opinion the only real difference in regs these days is the mouthpieces, and even those you can mix and match. The one thing i look for in a regulator is its ability to be taken apart and serviced in the field easily, that way if any caca hits the fan it's not a huge deal.
It's all about where you want to go with your diving career.
If you want to do mostly recreational diving, any gear you buy will be fine. Heck, you should be able to dive with a balloon for a BC when you get experienced enough. Any kind of mask, any kind of fins, any kind of gear. It shouldn't make any difference what gear you have on if you have trained your body and mind sufficiently.
If you want to go more towards the techie side, consider getting a BP/W setup. They are pretty nice, and you probably won't have to spend as much money. If you do go this route, please don't get one of the cookie-cutter pre put together packages. go but a backplate, buy a wing, and buy some D-rings and webbing. The process of putting your gear together yourself makes you much more familiar with your gear and will be more comfortable. Pre-packages deals just spoon feed you mush, and wouldn't you rather cook your own dinner? If you are leaning towards this side, make sure the reg you get is a diaphragm or a balanced piston, as they will give good performance at greater depths.
Oh, tanks, i totally forgot tanks. I prefer aluminum. No rust, no worries. no annoying tumbling or re-painting or any of that crap. just a wash every year and it's done. Aluminum oxide prevents further oxidation below it, while with rust you have to wonder if that tiny spot extends all the way to the edge of the tank wall. That's why i prefer aluminum over steel. However, steel tanks can provide more cubic feet of gas, so if you are willing to put up with the hassle, go for it.
Happy diving, let us know what you decide!