Hoelbrak hands down! The snow and the ice everywhere, the half-drunk norns lying on the ground, passed out oh-so-close to a bed, but not close enough in the end. The boasting and the random chatter from the people living there is absolutely hilarious for the most part!
Divinity's because the bank, TP and crafting stations are all very close
Funny you say that because DR's one of my least favorite cities to do crafting. Unless it's one of the few that happens to be right there next to the waypoint it's actually a decent run to get to the other stations. I think Rata Sum's actually slightly more convenient in terms of vicinity of bank to TP and closeness of crafting.
DR by a long shot. In fact, I wouldn't consider any of the other capitals a city, as they are too small and missing too many features. I might see them as an outpost or maybe a fortress, but not a city.