For those who don't mind being a few subway stops away from Seoul's more popular areas, the JW Marriott is a good mix of class and convenience. Rooms are new, clean, and (for Seoul) spacious, the service excellent, and one of the best hotel gyms in Seoul can be found here. As all rooms have free wireless internet and it's a short walk from Seoul's central business district, the JW Marriott is also an excellent choice for business travelers. Also, the hotel is located above a mall with a variety of shopping and restaurant options. Ask for a room above the 15th floor facing the river for spectacular views.
19-3 Banpo-dong , Seoul, 137-040, South Korea