Wow.. getting organized and getting everything out of your head is a lot of work! Especially when you've piled up years worth of 'stuff' that is not organized at all. I've been waging this GTD process war on both fronts... home and at work, and so far so good.
I quickly figured out why I wasn't putting things where they should be, i.e. filing paperwork, media, notes, etc. It was because I did't have a place to put it to begin with. After cleaning out my local hot file folder at work and moving all the old but needed items to an archive filing cabinet I now have a tickler file, general index file, and someday/maybe folders at the ready. I also have an indexed file set by the WO# in our IT work order system I developed to track out outstanding instances. This just makes it easier to find the paperwork associated with an incident instead of some alpha system.
I actually spent most of the weekend working through the home mess instead of working on My Car.. but the 'build list' is next for a revamp into Next Actions!