Best DM Aids?

[Grogg of the North]

Prep:
-Research material (books, movies, video games, wikipedia, anything that helps get those creative juices flowing)
-Red computation notebook. (Sometimes called a laboratory notebook I think. I've come to love using these for writing my DM notes)
-Post-it Notes. (The little strip ones work great for bookmarking monsters, spells, etc.)
-Rule books. (They never crash, run out of batteries, or require passwords)
-Time (Why is there never enough time!?)

At the table:
-Water! (You're talking. A lot. Have something to drink while you're doing it.)
-Books. (See above)
-Mat and markers (We use a battle mat with wet erase markers.)
-Dice (I have a large dice collection so I tend to use dice to represent monsters. It helps me keep track too of what's been damaged. Also, you know that someone is going to forget their dice someday so it helps to have extra.)

 

[Lanefan]

I actually prefer to play without maps and just to "theater of the mind". You can still do all the stuff you describe without maps.

In the moment, absolutely. But you either have to have a godlike memory or take ridiculous quantities of notes in order to have things be in the same relative places when the party goes back there the next day/month/year and it's been a week/3 months/5 years since you DMed that bit...

Never mind that whenever I try running without a map I invariably end up describing impossibilities or inconsistencies:

PC to local militiaman in central town square: "Excuse me: which way to the Dancing Dragon?"
Militiaman: "'Bout a half mile southeast, next to the big Zeus temple. <points> That road will get you there, and look - you can see the temple's tower over that roof."
Player: "er, Mr. DM, you just told us the big Zeus temple with the tower was on the west side of town and that we passed it on our way in..."
DM: <facepalm>

Perhaps not the best example, but you get the idea.

Lanefan

 

[Silver Moon]

Maps of our 21st century world translate well into mapping areas in D&D worlds. Several times I have taken maps of either distant states or Canadian provinces and used them as the template for a D&D region. Interstate highways become main roads, state highways become less-traveled roads, cities become large towns (current population/1000 works well), towns become villages (current population/100), keep lakes, rivers and coastlines the same. Just change the names (although current County names often work for the renamed communities within that county). If you still think players will recognize the area then invert it either 90-degrees or 180-degrees.