Take a look at your favourite travel photos in the past and see roughly what focal range they were at, then go through the following and see what else matters:
P14/2.5 (wider than normal, very cheap bargain, pancake)
O17/1.8 (expensive, great f/1.8 performance)
P20/1.7 (great f/1.7 performance, pancake, slower AF, banding issues on some bodies!)
PL25/1.4 (larger, expensive, not so close focusing, great f/1.4 performance)
My pick would be the O17/1.8 or PL25/1.4 for a strict normal, depending on your favoured FL. The P20/1.7 is a cheaper and more compact in-between alternative for those two, if you don't mind the slower AF and you don't have one of the dreaded banding bodies (E-PM2, E-PL5, EP-5, EM-5, GH3). For a real bargain, if you like the the 28mm equivalent FoV, go for the P14/2.5 - it's a great little lens. It's wide enough that it could even complement the PL25/1.4.
I personally use a PL25/1.4 with my EM-5 and love it for all sorts of everyday normal shooting. The shallow DoF, sharpness, colour, and low light performance is excellent. For travel I tended to favour a 28 mm equivalent FoV, however, which I'm covering with the O12-50/3.5-6.3, but I'm VERY tempted to get the P14/2.5 for when I want to travel ultra light or when I need the extra stop.