Hmm, good question.

  Two cars: probably 50 in one and 20 in the other.
  iMac including internal/external peripherals: 10?
  2 iDevices: 8 more (CPU, touch controller, GSM modules?)
  My kitchen probably has 10-20 in various appliances.
  Kids toys and video games: probably 40-50.
  Cameras: 4-5
  Almost every SD card has an ARM core, so 30 more there.
  TV sets, Sat decoder, DVR: another 10?

I'd say 200 easily. I'd guess most households are somewhere around this number.