Was going to say the same! Whiterun is the most attractive city to me. It also reminds me a lot of Edoras from LOTR (films) which it was clearly heavily inspired by.
Markarth though is just an enchanting place. Feels ancient and the layout is just awesome with the streams coming down off the mountain and the guard tower dominating everything. Definitely the most unique city in the game.
One thing that is great about Skyrim is the cities, definitely compared to Oblivion. Oblivion's cities were very... boring. They really stepped up on that here.