I agree if u have 2 bodies, it is good to carry one with a wide lens and and other with a long lens (I usually prefer zooms). But then again the weight is a big consideration. I do carry 2 bodies on trips. Serve as redundancy too. V flexible for most situations.
I also agree if u can afford (both $$ and muscle) to carry large aperture lens (of course for zooms it would be the f2.8). The large aperture eg f2.8 would be useful in low light or to keep the focal plane very tight around the subject (ie blur the background).
I believe I got the muscle to carry the big guns ;p but don't have the money to buy any one of the trinities without selling off my current lenses :dunno:
And primes are much smaller and lighter to carry around and has bigger aperture too :bsmilie: but a lot of footwork which I doubt ANgkor Wat has room for...