As an integral part of getting an event of this size off the ground, I have a spreadsheet to store conference contacts and budget calculations. With Google Docs, I have been able to share this important info with various associates whenever they need the information. It's much easier than having to look up the accounts one by one, then pasting them over and over again into an email or instant message -- where the information would remain disorganized in any event (no pun intended). Also, keeping them stored online via Google Docs allows me to keep my hard drive cleaner, and not worry about the need to back them up so they are never lost (which would be disastrous when organizing a conference of this size).
