Game Aids

There's only so much RAM the average Storyteller has in their brain to deal with all the various intricacies of a roleplaying game.  Different Storytellers handle different calculations and decisions more easily than others depending on their personal interest and experience.  A Storyteller that loves combat and pores over fighting styles will run a smoother combat scene than one who's shy about mechanics and rarely runs a fight scene is going to struggle much more.

So I thought I'd compile a list of what Storytellers of various persuasions have to deal with and some possible Game Aids that can help.  If you're reading this as a player, hopefully it will help you gain some sympathy and appreciation for the many angles we handle.

Combat

• Typed pages with PCs fiddly feats, mechanics, and spells on it so they can handle that
• Similar typed pages for some NPCs
• Pre-made Status Cards so you don't need to hurriedly look up the Sickened rules
• Pre-read important feats, mechanics, and spells that are likely to be useful (such as drowning rules on a ship-based encounter)
• Magnetic Initiative Sheets

Encounters

• Monster Cards (so that you know which monsters are in that location)
• Random Creepy Instance Cards (floorboards creak, strange breathing sound)

Investigation

• Props that you can hand players (buys you time while they read them - Call of Cthulhu has plenty of examples of these)
• Timetables of suspects' movements (so you don't contradict yourself by having one person say the count was in a pub while he swears he was at home with his wife UNLESS that is a clue)
• Clue Cards (they roll Perception at a DC 15 and you give them a card detailing the clue - it also forces players to conceptualise it in their own words rather than simply say: "What she said" after you finish describing it)

Social

• NPC Face Cards where you can scrawl on names (faces can give indications of personalities)
• NPC books from this current system
• Pre-generated NPCs (I'd suggest card-sized with a face attached) - a quote helps
• Interaction Cards (best for big scenes where you have some interesting things for them to overhear, gossip to come up in conversation, or altercations for them to witness - helps most in political games with a large number of players such as a vampire court)

Location Descriptions

• Floorplans give physical details at a glance (Sims 3 and Dungeoncrafter can help with these)
• Numbered Rooms with short descriptions (helps save you translating pictures to words)
• Props and clues in italics in the Numbered Rooms (or in a floating list so you can insert where the players look)
• Put obvious details in bold and put them at the start of the description so that you can edit in, or out, the fire vampire from the living room depending on earlier player actions (so you don't have to try and remember where you put that Fire Vampire if it's important to that location - if not, floating monster cards are better).
• Grid Maps (for games where 5 foot squares matter so you don't need to pause, visualise and calculate)
• Dioramas (for ones where location matters but 5 foot squares don't - can be remarkably atmospheric if rarely used, if time-consuming to create)
• Miniatures (so that you don't have to try to remember precisely where everyone is standing and whether PC #1 is behind PC #2 or in front of them)
• Store Descriptions with a run down of their current most intriguing stock to distract players who wish to go shopping (especially in D&D or Pathfinder) and give them a sense of immersion and culture while you run encounters for the others.
• Pub / Restaurant Descriptions with Menus (not a full menu, but a few drinks or meal choices can help you when they go to that Abyssinian restaurant you mentioned and order a meal)

Loot & Equipment

• Item Cards (saves on description time, distracts some players while dealing with others, and covers all those: "So what IS in his pockets?")
• Gun Cards with Ammunition Markers (if being on your last bullet matters)

 I've used all of these at some stage or another but not all at once because not only would it take a ridiculous amount of time and effort on the periphery (thus not really aiding much) but you'd require a DM desk all of your own just to cope with the weight of ALL of that information. 

Which ones of these do you find most useful?  Can you think of any other useful Game Aids you've used?