Sons of Muspel army, but to another gamer who also had the bright idea of using some of the translucent resin D&D minis as elements for HotT (except he has a lot more figures, in numbers and in variety). Note the bases, where the elementals are literally melting the stone where they step.
This photo comes from a Hordes of the Things big battle at the 2008 Fall In convention. You can see more photos of Unseen University invading the Elemental Plane of Fire here. It's given me some inspiration to expand my own fire army.