First was a shiny Girafaraig in the Sapphire Safari Zone. It ran away, and I eternally despise the Safari Zone.
From there my only random shiny encounters have been an Unown V in Leaf Green and a Diglett in Heart Gold, both of which I caught. I also SR'd for a shiny Giratina, which I finally caught after a few months of on-and-off resetting.
Official Dictator for Life of the Super Smash Bros. Brawl Boards