In England, most of the services in towns have the mains run under the street with underground services tapped for each building.
Overhead services are used in more rural areas. Here's an older style service:
Newer drops use a cable with concentric neutral (this one has clearly been converted from the older style, as you can see the spare insulator):
Here's a wider view of the same drop:
You do sometimes see cables run along the wall of a building. We have a lot of what are called "semi-detached" houses in Britain (what you would call a duplex in the States), and where these exist in rural areas with overhead feeds you often see a single drop to one corner of the building and separate feeders tapped from the bracket to each half of the building.
[This message has been edited by pauluk (edited 05-30-2003).]