I'm worried about the order they will change the kits each year. Each shirt should be given a 2 season life span, rather than changing them all like we did this season. No matter what way you look at it, it's a ripoff when that happens. I especially don't want them changing after a year, now that the quality is so good as well!
I'd say keep the home and third shirt for the 2009/10 and 2010/11 seasons. Change the black shirt at the end of the 2009/10 season (to a kit like the Wembley '99 shirt!) and then alternate in this way.
It's proper that the home shirt alternates seasons with an away/third shirt, rather than alternating with away/third, since people may not be too willing to buy two different 'away' shirts in one summer.