If your criteria for "non-traditional" is a step below Paris and Rome, then that opens up the options quite a bit. I've always enjoyed traveling in Central and Eastern Europe and have almost universally had good experiences at Hilton properties in the region. Cities where I've visited solid Hilton properties include (west to east, roughly): Prague, Vienna, Bratislava, Budapest, Krakow, Belgrade, Kosice, Bucharest, Sibiu, Sofia, Moscow. Not all luxury properties, but enjoyable stays with generally good amenities and service.