I build mainly Sci-Fi and Castle, though I'm currently and obviously more focused on the latter. I also enjoy landscaping - particularly rockwork - and so there's often a lot of that mixed in with my mocs. I love to write as well, and so put a lot of thought and work into the stories I include with my mocs.
Possibly my favorite builder and best friend on the 'Pages is Halhi 141, a great builder who is quite well-known, particularly for his fantastic rockwork. A less-known person whom I consider a great friend and always-improving builder is Lindel Baskin; I suggest you check out his mocs!