Obviously the most important pieces of artwork are the covers. Well, cover, for now, but Journey to Altmortis will have its own cover sooner or later. It'll also be a handy place to put maps and maybe other bits and pieces. The Geldfels and Kemelheim crests are pretty simple but I might put those up as well.
Covers and other bits of artwork are always a bit troubling. As a writer just about everything from the story to the characters to the work rate is down to me, and yet the biggest single hook is the cover, which someone else does. I'm very happy with the Bane of Souls cover, but I'm having some difficulty settling on an Altmortis cover.
I could hand the map over to someone rather more artistically inclined, but it's something I'd rather do myself. It won't be the most aesthetically pleasing cartographic endeavour in history, but it will be accurate.
Mind you, for the subsequent trilogy there may be several maps. I've got a basic map of Denland done (I need to rename one city, though) and battlefield/local and maybe even city maps may need to be done.