I dont know whether this is good or not but I prefer
myList.SelectedIndex=myList.Items.IndexOf(myList.Items.FindByValue(value))
because this way some times even if the value is null(retreived from the
database, or the session expired) this will still work. But if you do the way
Steve mentioned you need to catch a null reference exception. So its up to you
how you want to use it.