Everybody already says AT-AT's are AT-ST's moms, but it occured to me to make a scene of one actually mothering a pack of them
The models are not mine (to lazy to make them, besides, you can find them for free). So all I did was add joint connections to the parts, pose the models, add textures, create the snow as a terrain object in 3ds Max, and render using Mental Ray.
Later in Photoshop I added some fine snow track and other deformation details to give it a bit more realism. And of course some subtle url's to my site, because this will surely get stolen by one of those wallpaper sites.. so instead of adding an ugly watermark, I decided to take advantage of some unsolicited advertisement to my site.