In the places I've stayed (mostly in the South) houses are generally single storey. In the south you also see some houses on stilts a bit like they have in Queensland and the Northern Territory. You will certainly see quite a range of fashion in the cities - Bangkok in particular. People will mostly be a little more casually dressed than in Japan, because its sooo hot. I guess you'd say the dominant dress sense is casual but modest. You won't see as many outrageous outfits as you will see in Japan. Most of the time people (both men and women) prefer to wear long pants and short sleeved shirts. I guess if their jobs demand suits, they dress accordingly.