Managing NPCs

NPC interaction is a cornerstone of Olde School Wizardry, my home brew RPG -- much more so than combat, exploration, or crawling through subterranean vaults.

In fact, after about six and a half years of play we've built up a stable of nearly 200 non-player characters.  There are dastardly spies, incompetent wizards, scheming artificers, and stalwart clansmen ... a masked vampire, mercenaries, and vindictive professors.

A good NPC requires a few things:

• a face -- I use black and white photos for most of mine
• a goal ("kill all wizards," "rescue my wife from the camps," "become ArchChancellor")
• a secret -- he's plotting to ruin Sir Kahn's reputation, she's actually a flame elemental
• a voice -- an accent, a distinctive speech pattern, or a catch phrase
• stats -- only as many as matter ... most of my NPCs have 0-3 mechanical notes

However, managing all of these personas consistently (and distinctively) requires some effort!

One thing I do to keep it all straight (and just as importantly to help my players keep all these characters sorted out) is to create a simple 3x5, index card for each.

Photo and name go on the front for my players -- a clothespin or clip help these stand up for a table display -- while notes on accent, goals, alignment, and any stats I've generated go on the back for my reference.

Have you ever managed a large stable of recurring NPCs?
What tricks did you use to keep all the details sorted out?