Diagnostic Tools and/or Kits make great Christmas gifts for people that are fixing their own machines or like to tinker For some reason that stuff doesn't really get thought of as much, but they're kind of the gift that keeps on giving as someone expands their knowledge about fixing machines. Mainly useful for people not buying the brand new machines.. and instead tinkering with older project machines they pick up & looking for easier methods/tools to repair the machines.
http://www.pinitech.com - Kits, Upgrades & Test Equipment for Pinball Machines (shameless plug)
December Sale -- https://pinside.com/pinball/forum/topic/pinitechcom-december-sales-on-diagnostic-tools
Additionally there's a few other guys creating some neat tools:
http://www.siegecraft.us - Pinball Diagnostic & Test Equipment
Lindsey @ http://www.pinforge.com has some neat stuff coming as well for Classic Bally/Stern (I think 2016'ish)
Aside from being one of the guys making the stuff.. if it was circa 2008 when I just got into the hobby, I'd have been *thrilled* to get some neat kits or diagnostic equipment for Christmas.