Undisputedly the most important part of your saltwater tackle is your swimming trunks. We can't help you there.
The second most important item is the reel. It is imperative that your reel is anodised and as hard as nails. Also, because lightning fast 200 yard runs are more than a possibility, it needs to have good backing capacity and a superior drag.
Trevally, for example, are known to explode reels and create serious meltdowns. To avoid this interesting tragedy get hold of a great reel. The Teton is such a reel. Look after it, rinse it and lubricate it after every trip.
For the truly serious saltwater fly fisher I sell the Billy Pate.
For flycasting of any description I find fast progressive rods superior to any other. Both Redington DFR's and Scott Tacticals are ideal for saltwater fly, being crisp, light, progressive and robust. For travel a three or four piece rod is essential. Take it as hand luggage; otherwise you will probably find yourself handcasting.
When you buy saltwater fly lines make sure that you buy the correct one for the circumstances; it is no good having a cold-water line in a warm environment, such as Northern Australia. Believe me, I know. Been there, done that.
First choice for many anglers is a floating line. For sight fishing this makes sense. When fishing blind, intermediate 'slime' lines are useful, with the occasional Hi-D foray.
Just as in trout fishing, there is a serious advantage to be had in going light. But it's all relative - if your trying to catch a sailfish with a fly the size of a coconut, or even with a coconut, then you need a heavy outfit. If on the other hand, you're after bonefish or trevally then a lighter affair would be more appropriate.
A good all round compromise is a 9 foot AFTM 8 - basically this gives you the momentum to get that big lure out there. If you are explicitly going for the small stuff then you could drop it down by a couple of ratings. But if you've got bigger things on your mind, or more specifically want to chuck bigger and heavier flies at them, then a #9 or even #10 weight outfit would be better.
Perhaps one of the most useful recent additions to the flyfishers tool selection is the Ketchum release.
Angry, spiny, toothy fish are best handled without hands, if you know what I mean. Also some fish disappear under the sand if you give them half a chance. The ketchum gets your flies back!
In Australia, Target will sell you a cheap pair of 'cozzies'.