Having trouble getting pfstat to display decent graphs? Then you’re probably missing the following line at the top of your pf.conf file:
set loginterface rl0
Where rl0 is the interface you want to grab the statistics for. I’m not entirely sure how to get the statistics for multiple interfaces, but when I figure it out, I’ll let you know 
Good article on how to get NFS running in OpenBSD:
Perusing through some links today, I discovered a tripwire-type system in OpenBSD called mtree (man mtree) which looks really kewl. You cang generate a profile for your system and then compare your filesystem against that profile and detect any changes that have been made. Lots of interesting options there, something I’ll definitely have to play with later.
Couple of other interesting notes, you can set additional attributes on files called flags (man chflags), which, when enabled, can stop even the superuser from deleting or modifying a file. The flags can be reset, but only when you drop the system down into single user mode.
And finally, for some more good reading, check out the definitions for each of the securelevels (man securelevel). Good in case you were ever wondering what that sysctl variable was used for