The S'rulyan Vault II

From publisher blurb:

Like the first S'rulyan Vault, this is two extremely high-resolution dungeon maps in both old school blue/white and bloody parchment hue. The dungeon is huge and contains a variety of cavern and traditional room/corridor areas... along with special icons.

In addition to the maps, there's a PDF with advice, random tables, and various aids in creating and GMing your own dungeon. I've used these in my own games and - believe me - they help.

A warning before purchasing: one image might be a little racy for some folks. Those afraid of b/w old school illustrations of side-boob and what could be a demon's flacid balloon should steer clear of The S'rulyan Vault II.