I need to keep a better version of our server/infrastructure diagram (showing their logical arrangements, IPs, roles, etc.). I’m outgrowing graph paper and could really use an electronic version, either web-based (ideal) or with desktop software (OS X).
What do people use for this?
My answer didn’t seem to get posted.

Our managed hosting group uses Microsoft Visio to spec out infrastructures for customers … it doesn’t really sync up directly with Marco’s requirements (specifically because it’s not OS X-native), but we’ve found it the easiest to use.