There were so many wonderful entries in the Mini Castle Contest. I want to go back and look at some other in addition to the great winning entries I've already noted.
Knight Eklund's Cliffport Castle has a really beautiful sweeping coastline. I really like the color scheme and the variation in slope pitches from the upper plateau down to the beach. The castle itself is great with a non-square shape. I assume that most of the objects are held on by gravity, which is a liability of using the SNOT base. Another minor liability of the SNOT base is that it makes everything so unnaturally flat. Of course, at this scale, studs make fairly large hills, so maybe flat is better.
Ru Corder's Countryside Keep is also on a SNOT base, with the same advantages and disadvantages noted above. The wall made of brown rods is outstanding, as is the sandwiching of grill plates to make small windows in the main keep. I also really like the tree design using flower stems. Oh, and the use of log bricks to make plowed fields is another great piece usage.