|1e AD&D PHB|
|GW Blue Book D&D|
|9th Print 1e AD&D DMG|
Well, for me it's gotta be the first edition AD&D PHB, and yet I never owned, played or DM'd this version of AD&D. This cover is deceptively simple and features no heroic action unlike other covers, yet manages to capture essentially what happens in every dungeon crawl. The Rogues engage in a little post fight thievery whilst the Fighters argue over which way to go next and the magic user leans on his staff exhausted after blowing the last of his spells on a mid dungeon minion. You can also buy this iconic statue as a dungeon feature for your own games from Otherworld Miniatures.
The first version of D&D I owned was the 1e Blue Book produced by Games Workshop. Sadly I was too young to really appreciate it, but it did start me out in this wonderful hobby. Looking at the artwork, although a beautiful piece of pen and ink, it's not exactly evocative of the game contained within and harks back to the artwork of "The Hobbit" with it's Beardsleyesque detail.
The version that I most fondly remember having spent hours pouring over almost sucking the content dry was the 9th print version of 1e AD&D DMG. The artwork is quite powerful, suggesting that great secrets lie within and to get to them you must best the sinister figure standing between the doors. One of Jeff Easley's finest and subtlest works.