Volume Four of Moleskin Maps by Chubby Monster Games from the hand of Matt Jackson. If you read this blog, on Google+, read nearly any gaming blog Matt's maps are there. His map style looks so simple and eloquent. Like the rest in the series there are 10 maps included with 10 adventure sheets to go with them. These focus on underground maps, one with ruins. All the maps are useful. A quick flip through the book and its easy to come up with ideas on the fly to fill these caverns.
A few weeks back I needed something to get my brain going and I was drawing for crap, so I got one of Matt's maps out, numbered the encounters and soon I was going full tilt on a mini adventure. I don't know about most of you, but for me, the map comes first. It helps me develop the adventure. Sometimes I know what I want ahead of time, but its good practice to use other's maps to exercise your adventure writing skills.
The 4th volume of Moleskin Maps is fertile ground for ideas. And I've praised the utility of the adventure sheets in the past. I like the no nonsense layout. You get your maps and a tool to use with your map. Done and done.
So if your interested in getting some maps here's the other cool thing. Volume 4 can be had for only $2 on RPGNow. The other three volumes are currently priced at $1. So for $5 you can get 40 awesome maps. Go get them.