The following link goes to the adjudication decisions for security clearances put up for appeal.  These are contractor clearances with the DoD.

http://www.defenselink.mil/dodgc/doha/industrial/

I think this is a useful resource, especially in conjunction with the Adjudicative Guidelines that were linked earlier.  These appeals not only show specific instances of disqualifying conditions (DC), but also **AND VERY IMPORTANTLY** show in some cases what steps the applicant took to mitigate the security concern.   

TRANSLATED:  Look in here to find people with screwed up finances, lots of previous drug use and even arrests and foreign influences, among others.  Some of them who documented the steps they took to recitfy the situation (credit counseling/re-payment, attend 12-step program etc) and maintained their clearances.