My fav cities would have to be Ecruteak City because it has a ancient old fashion theme to it and it has a BELIEVABLE legend behind it I also like Olivine coz it close to the sea and Azalea Town because its a adventure going through Ilex Forest for the first time
Ecruteak City by far!!! It has this traditional Japanese feeling to it and it's very traditional in way of belief etcetera, I love it! The designs of the buildings are also very Japanese styled. Heck, the battle music for Ho-Oh in HG is Japanese styled!
Johto probably has the weakest cities comparing to all other regions, but if there's one city I like and that's Ecruteak. It's so mythological, and probably the most compared to any other city in any other region. Celestic actually does measure up, but it's debatable