I saw in the Google LatLong blog yesterday that Google has added contour lines to the terrain view. This capability was added by , a Google intern. Follow this link to the blog posting. Here is a map I made of Mount Washington in New Hampshire:
Mount Washington is the highest point on the east coast of the USA. I am not sure how they select the contour interval. It seems to be 40 feet. Here is another map of the Waynesboro Reservoir:
This one also seems to have a 40 foot interval, too. It will be interesting to check other regions, such as the Rockies. I do like the effect of contours and shading to show elevation. This is a great option. It turns the online maps into much more of a professional tool.