There are two: the first was the launch of Guardian Unlimited in 1999, which has expanded the reach of The Guardian exponentially, getting the brand into the minds of people who would never have been exposed to it. Business plans mean very little when you're working in a dynamic medium like the internet. You can have the most brilliant strategy, but if it doesn't work, you have to change it as you go along.
My best decision, though, has to be relaunching The Guardian as a Berliner.
Why? People are going to look at it now and say this was a no-brainer.