Had a long drive to and from the in-laws for the Christmas break (4+ hours each way), so had some time to think about this. I use Quicken to track all of my finances, and up until now, I had just put pinball purchases into a Hobby category (Hobby:Pinball, specifically). But the more I thought about it, the more I felt it should go into a physical asset like a car or house, rather than just a "it's spent" category. Every year on New Year's Eve, I go to KBB and Zillow to see roughly how much my vehicles and house are worth to adjust the values in Quicken, and pins feel similar from a value perspective.
So today I made a "Pinball Machines" asset class and when I buy a pin, I transfer the money into that asset (since that's roughly what the pin is worth). When I sell, I pull the money out of the asset class and into my bank account. It's a little more work, but feels more realistic since a pin doesn't lose value as soon as I buy it (NIB being the main exception - but it still has value and should be tracked. That, and I've never bought NIB). I went back through all of my purchases and made the changes for this as well - I've only bought five and sold one, so it was manageable to do.
I figure I'm the only one this obsessed with financial tracking, but on the off chance someone else is, I'm curious to hear how you manage it! And I put in an obligatory poll, because, well, why not? 
