Megaton Games
Explorer
To attempt to clarify my last random thought: Create a dungeon from a set of 3D tile pieces from a Dwarven Forge type set, then replicate in your pdf maps. That way, someone that has a lot of money in 3D tile sets can use them to replicate some of your maps. Sometimes the physical limitation of the tile sets prevent replicating a paper map layout.
On the hexes vs squares: if you are primarily doing constructed dungeon/buildings then squares are the way to go. If you do free form caverns or outdoor areas, add a hex grid option for those maps.
On the background shading: dark background is fine, just offer a less dense background that uses less toner. A brown shading vs a solid brown color. On a large map, can make a significant difference in toner usage. The last time I checked, a full set of replacement toners for my color laser was over $500. They last several thousand pages but minimizing toner consumption is still worthwhile. I bought the printer as a referb off the Dell site for $300 and it came with a full set of real toners. Would have been cheaper to buy a second printer, keep the toners and toss the 2nd printer.
Now I understand what you mean. Great ideas actually. Thanks!