There are so many threads that have been made about this.
Here’s a start:
http://www.unicyclist.com/forums/showthread.php?t=54859
http://www.unicyclist.com/forums/showthread.php?t=53199
http://www.unicyclist.com/forums/showthread.php?t=52449
http://www.unicyclist.com/forums/showthread.php?t=44396