you're going to get a gizillion different opinions. basically, i would say buy quality
to the ability of your budget.
BCD's: these are simple devices, and any reputable manufacturer will make a decent BC. go for fit and price. basically all manufacturers making BCD's today are reputable. the key here is going to be which style: jacket BC, back-inflate, or
back-plate and wings? do some research and try them out, see what you like.
i dive a backplate and wings, and love it. streamlined, light, easy to adjust, and
excellent trim and bouyancy characteristics.
regulator: the big five are Apeks, Atomic, Scubapro, Zeagle, and Poseidon. My favorite is Apeks. Zeagle and Scubapro make some awesome regulators as well.
Atomics are overpriced. Poseidon are hard to find and service. i would try to get the best reg possible. a trouble-free, quality regulator is a thing of beauty, and it adds to your safety while diving.
computer: oy vey... i say buy the cheapest computer that does what you need.
i really like the Aeris Atmos family of computers: cheap, reliable, and complete, with
no frills. i would avoid air integrated computers. you are basically tripling the cost
(shops LOVE to sell these, for that reason).