I can't choose just one. It has to be two.
First however, over the other, I'd say the Artwork section. This is a given in that I am a resident artist here and have been for years now. Naturally that forum is my more favored of the two, as I use it regularly to add more of my work or view and reply to the work of others. I like to see whats going down these days artistically with our other artists and keep up to date, and that forum allows me to do that.
Second to the Artwork forum is this forum, the General Discussion. It allows me to gain a deeper understanding and appriciation of the people here on a personal level. And thats whether I participate or not in any given thread. It is this forum, in my opinion, that is the heart of this entire site and that, without it, the community would not exist in as wholesome a state that it does, nor would it be as personable or friendly.
I enjoy this forum much for the same reasons I enjoy the artwork forum- it allows me to witness and partake of the community in a satisfactory way.