Keith
another congrat from the other side of the planet. I've too the FM3a and I'm very happy with it. I agree with those suggesting to get a silver model if you can (better look and probably slightly higher value if you want to resell)
About lenses, this is what I suggest you:
1) try to make a kit with only one filter size (52mm). It's possible and here's how
a) Get the 105 F/2.5 AI-S, really one of the best ever Nikons, which is easily recognizable due to the integrated hood (nice touch) and the silver ring where focus marks are
b) Before getting any other lens, 50mm or 35mm (of course everyone here lusts for ZF build quality) try to think differently for a moment. Maybe a CV 40mm F/2 might serve you as good as the others and be exceptionally compact (it's a pancake) - hint: if you get it, the FM3A should be BLACK. (while Nikon pancake, 45 F/2.8 is SILVER, so should be the camera if you could) Both CV and Nikon are two great lenses.
Give a look how "little" it is with the 40 on it: it's the camera leaning from my right shoulder in this funny picture (compare it with the F6 and the flash hanging from my neck)
c) lots of options: 28-50 F/3.5 (already suggested): 52mm filter thread, as well as 28 F/2 AIS and CV 20 F/3.5 and Nikon 200 F/4 AIS (I have the 40, the 105 and the 200, I still have to get the wider ones and eventually the zoom)
Flash: A very compact one is the SB-22s (I have it too) - Note that the FM3a has even a button for fill-in backlit shots. It's the one mounted over the F6. Be sure to get the newer SB-22s (improved in 1997 and able to work with more bodies than the older SB-22 version, with a 1987 design and compatibility)
The only thing you might have to learn (if any) is the metering (60% center, 40% sides) which can be tricky. FM3A doesn't have spot metering as OM.
Bottom line, I'm setting up this kit for my trips in those countries where security might be an issue and where reliability must not depend on batteries. If you plan to work in A - mode, one of the simplest symptoms your battery is dead is the mirror staying up and the shutter which doesn't open. Back to manual mode, it works again, but since exposure meter will be off, the only way in this case is being trained with the sunny 16 rule and do everything manually.