[whpalmer4]

Are you mounting any network disk volumes, such as the MobileMe iDisk? If you are, and leave the network where you did before dismounting them, OmniFocus (and other apps) will probably hang when they next attempt to open files on any of your disks. After a minute or two, if all goes well, you'll get a popup window alerting you that the server has disconnected you and the machine will be usable again. Try unmounting any network volumes before leaving the network and see if that doesn't avoid the hangs. It doesn't sound to me like this is necessarily an OF issue, just that OF happens to be the app first attempting to access the disk.