A big one that still inspires me is the World of Greyhawk boxed set from 1e. When my 11 year old self unfolded those hex-maps of Oerth, my jaw dropped. I wanted to go everywhere.
You beat me to it, so I'll merely stand by and second this; though it was the 4e Worlds and Monsters preview book that did it for me. Hell, in essence I got an entire 5-adventure arc out of two pictures in that book!1. The 1e DMG, especially the Artifacts section and its many hints of lost cvivilisations and ancient magics.
2. The World section of the 4e DMG, in particular the spread picture at the start of it with the adventurers looking into the distance. The 4e 'setting' art in general is very evocative, and a real breath of fresh air after 3e's dreary art style. I like the Worlds & Monsters art a lot. I was so glad somebody at 4e finally 'got' the importance of landscape/setting art. Maybe Peter Jackson was an influence there? 4e's focus on style & atmosphere in general is a huge step up from anything I've seen from the D&D brand since about 1983-84.


(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.