There are times (emergencies, impending power failures, drinks spilled on the tower, etc.) where shutting down one's machine now (preferably by disconnecting the power cord) is the best course of action.
Of course, this can be potentially dangerous as it can cause heavy data loss, both on the filesystem side and the application side. The filesystem doesn't sync and may get some inconsistencies (not a problem with ext4, but I'd rather not fix NTFS again), which are either a pain to repair or are (somehow) irreparably damaged. Similarly, applications not getting the ability to gracefully kill themselves just to give them a chance to quickly save any data again has the chance to be excruciatingly annoying.
Therefore, in the event of a sudden-poweroff situation, what steps (if any) can I take to ensure that my system is in a (relatively) clean state when I'm forced to pull the plug?