If you haven't got Google Earth you are missing a great deal - they have just updated my local area to better, though not the best, photos.
Yesterday I did a circumnavigation of Tan Hill
The link takes you to a placemark of the hill - described as:
Google has captured the (joint) highest spot in Wiltshire with a sprinkling of snow - this highlights its height above the surroundings. In this ancient landscape with Avebury and Silbury Hill just to the north and Stonehenge a few miles to the south it isn't surprising that the land is full of archaeological details. With the snow and the undisturbed downland you can pick many of these out. There are round and long barrows and the famous Wansdyke and other sundry ditches still awaiting an explanation. This used to be the site of an ancient sheep fair from time immemorial to the 1930s when the introduction of lorries instead of droving made the site impractical. This is a wonderful wild and lonely place to walk.