My go-to combo is the Ka-Bar Cutlass machete and the Ka-Bar small sheath knife.
There's not much else you need to do on your own in the forest that these two things won't do. They hold an edge and if you keep them reasonably clean, they'll last your lifetime. Best of all, they're slim and easy to pack.
I'd add this handheld job if you think you will need to get at larger pieces of wood.
Of course, if you're not concerned about weight and portability, get a fuckin' axe.
I personally have this on my list
but haven't tried it yet
This is supposed to have a ridiculously think blade, making it a near hatchet hybrid.
For coconuts tho, wouldn't some sort of electric saw work best? Just in terms of time and effort on that scale; it seems like something that would be useful in that it would also function for home improvement projects.
If, for some reason, you would like to use a fold out saw, I would think http://www.amazon.com/gp/product/B000CED1OG?psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s00
It comes highly recommended on most reviews that I've seen
Here are some Amazon links. May find them cheaper elsewhere.
KA-BAR 1246 "Camp Knife" OOP, here is a close replacement
This Get one.