Seoul is one of those cities that looks a lot better once the lights are off.
Crossing the Han River to the north or south can be pretty ghastly in the daytime. The river is surrounded with commie-block-like apartment complexes for miles and miles. I'm sure they serve their purpose, but man are they boring at best, and ugly at worst.
Nighttime is a different story. The sparkling apartment and office lights dotting the rivers and hillsides make for a very pleasant driving experience.
It's a nodal city though, and with nodal cities, you get interesting architecture spread throughout the city, rather than all within a traditional CBD. If Vancouver was to learn anything from seoul, it would be to better utilize space - alleys especially. The alleys in Seoul are its best feature.
Anyway, here's the same view as the other picture, but at dusk.
And the Yeouido skyline looks good day or night. It's the only real "American"-like skyline in the metro area.