Unless you're going on a safari.... A Normal and a Wide angle lens will do 99.99999% of shots for me.

I'd go medium format (6x6 or 6x7). Any camera with a 80mm lens and a 50/60mm wide option.
I currently own a GF670 and that package has covered 90% of shots I take. Would love to have a GF670W to add to my next trip but at current prices I guess that means either the camera or the vacation!

Personally, the less options I have, the better! So I'd say carry as little gear as possible. This isn't a comment on weight concerns but rather of a mind set.
While travelling, especially to a location I've never been to, I do get visually overwhelmed by the plethora of novel possibilities. Making choices as to what gear to use for which picture became a burden and a source of anxiety that just has no place in a trip.

I'm a firm believer that in any creative process less options is more. I have seen this to be true on more than one occasion and on more than one medium.