Just bought the Sony NEX-6

Only buy the e-mount 30mm macro if you intend to shoot food or things that don't move. You will not be able to shoot insects, for e.g., because the 30mm macro will have to be about an inch from the insect to get meaningful pictures. Not many insects will sit around for you with your lens an inch from them.

Good for food shots though, even then, I found myself pointed almost into the food for really close-ups.

So this lens is not really recommended. A better macro will be at least 60mm.

If you shoot raw, you will need to download the lens correction profile for the 16-50mm kit lens.

16-50 will cover landscapes to portraits. You will need a telephoto zoom when travelling, there are so man situations in a foreign land that do not permit you to "zoom with your feet". This is where the 55-200mm will be useful.

Shoot RAW + jpeg, or just RAW if you process all files.

Buy a second battery or a third with an external charger; you just CANNOT last a full day in Vietnam on just one battery; I would seriously buy two extra. In camera charging takes 4 hours, external charging time about two hours, so factor those hours in, otherwise you might leave your hotel with half-charged batteries.

The bokeh you saw in the catalogue can only be gotten with the 50mm F1.8, so don't be misled. THe 16-50 will not be so blurred as its aperture is 5.6 at 50mm.

So it's like you will want extra batteries and charger, the 55-200mm zoom, the 50mm f1.8, both together will cost you another Nex-6.

And not too long ago you only used a $99 p&s?

This Vietnam trip is really costing you. Then again, it will be an experience of a lifetime if you have never been there, so bon voyage!