Which reports are most important?

Hey all,

I'm involved with helping SANS organize the logging summit this July. As
part of that, I was hit with a question that I thought could be best
answered via feedback from the group.

What do you feel are the top 5 reports a centralized log management
system should provide?

For example, a few I came up with:

Authentication failures (Web, system access, VPNs, etc.)
Access failures (HTTP scripts, recursion requests, etc.)
Initialization of new/unknown processes
Unexpected outbound traffic through the firewall (IRC, TFTP, SMTP, etc.)

I would love to see a similar list from other folks on the list.

Cheers,
Chris