While many say, learning hanja is not necessary, I think it at least helps aquiring new vocabulary. My vocabulary is quite basic (which means I can understand basic sentences but not follow a discussion, not understand the news titles on TV, not reading a newspaper or a book...). I decided that I really have to learn more words, but since every word is a really new word, I have problems remembering them.
Don't listen to Korean people who tell you you don't need hanja. The truth is: they don't need hanja, but you do (at least me). When someone is learning something, the best way to remember is to link the new thing to something known. Except the transparent words in Korean, which are mainly English words proncounced and written in a Korean style, a westerner really has nothing to link his new words to.
However, once you know 명 (名) stands for "name", it's much easier to remember words like 명작 (a masterpiece), 유명인 (a celebrity) or 성명 (a full name). The hanja itself doesn't actually help in either the meaning or the pronounciation by itself, it's just another thing which you can hook up other words, make other connections. For example, this hanja consists of two pictographs, 夕 (crescent moon which suggests a dark night) and 口 (mouth), so you can make up the meaning: "talk in order not to be hidden in the dark" which means that others get to know me, hence, NAME. The next time you encounter the crescent moon pictograph or the mouth pictograph, then they won't be unkown to you and will help you connect new words to the known ones.
Not to mention that knowing hanja will let you learn Chinese or Japanese more easily when you get to them next...
By the way, if you are interested in the etymology of hanja, like I explained above, I'm sure you will be fascinated by the following website:
http://www.kanjinetworks.com/ . Even though it's targetted at japanese learners, the etymology is the same in Korean. Don't be afraid of the simplified kanji vs. the more complex hanja: they mention "FORMERLY" followed by the shape the kanji had before simplification, which is the form still used in Korea.