You probably have the file /System/Library/CoreServices/ServerVersion.plist (installed by the update), which causes the login window and About This Mac to think it is X Server; SystemVersion.plist should be the one for X non-Server.
It tells me that I don't have 300MB of disk space on my boot volume. I checked. I have 2.7 gigs. Curse you update, why must you turn my computer into a computer of LIES?