Kuk Sool Won is a very comprehensive martial arts founded by two Suh brothers - In Hyuk Suh and In Sun
Seo (Suh).
Although I have not studied it personally, I know the training is very similar to Hwa Rang Do, which I studied. Both of them are not like Tae Kwon Do, which has very heavy concentration to kicks and punches. KSW and HRD also concentrate on joint locks, breathing, grappling, weapons, etc.
I would highly recommend KSW to anyone who's serious about martial arts training, and if they are lucky to have found a place that do teach it. (It's not easy to find KSW school)