Going to Itaewon is a little like a Korean version of Tiajuna. Plenty of people willing to take your money. It is the favorite hangout for the soldiers so plenty of short-haired men are running around. At night, the place is wild and full of drunk people.
There are some good deals on clothes however. Silk ties for 3 dollars and tailored suits for 100 bucks. Itaewon is known for leather goods also and cheap prices.
Mike's Gallery, next to McDonald's, offers some great hand-made paintings for reasonable prices. I bought a huge hand-painted scroll mounted on silk for 30 dollars.
Near the mosque is a great second-hand English bookstore. For those in need of literature, I highly recommend visiting this place. There is a wide variety of books there and even some first editions and the such.
For eating, Gecko's is quite popular and offers a nice menu of American-style food. The chicken sandwich is quite good. As for bars, there are plenty to choose from. At midnight at the Grand Ole Opry, the play "Proud to Be an American" and it is fun to hear the soldiers sing along.