The new Nanos have a similar design to the old Minis and more battery life. Since my old Mini survived a fall from waist-height onto tamac with just a little scarring of the aluminium shell they should be durable enough. The new Shuffles should be even tougher - the weak point in the Nanos is the screen - and the Shuffle doesn't have one.
All in all they look pretty good - my only complaint would be that the batteries are sealed in, which means that when the battery dies in a few years time you'll need a new iPod.