In the United States, we customize cruisers. In Europe, customization of street bikes of all kinds is very popular — perhaps most popular in Germany.
Pictured on the left is an R1-based streetfighter, with a Hayabusa-based streetfighter on the right. These bikes, and more, can be seen at SickestBikes.
The U.S. seems to be trailing this trend in Europe. Europe has been wild about standards for quite some time, and now that trend is catching on in the U.S. Streetfighter customization might be one of the next big trends in U.S. motorcycling.