I am, I may modestly say, a gun at Photoshop, so I am hard to please when it comes to using anything lesser. Avairy is impressive. A collection of online tools to do a massive range of creative things. Check out some of the links … I must be slow, there are plenty of time-lapse and other examples on the site, and on YouTube.
So for those classrooms stuck with Paint or PaintShop Pro (yuk), or lack the budget to buy audio editors or Flash (Adobe own the creative world) … this is a real classroom option. Simple for the slower kids to pick up and useful enough for the top end to extend themselves.