The regular stories- While I may read some stories from Anthology, I tend to read more of the Hosted Author stories as well as a select few in e-fiction.
Live Chat- I must admit that I probably spend way too much time in chat, but it's a lot of fun.
The 'community' feel and aspect of the forums- I am still an active member of the forums and happen to enjoy the discussions we have. I particularly enjoy story discussion and political discussions as they are more interesting to me than the rest.
If I could choose a fourth, it would probably be the blogs, because you can find out a lot about people and their lives from their blogs.