CCTV coverage is already high in London, and increasing everywhere. Recognition software (not just facial) is getting quite good.

Cash can mostly be tracked unless you just trade with black/grey market sellers. Adding RFID to notes and mandating readers on cash registers would already be feasible.

Home devices (TVs, DVRs, even fridges[1]) increasingly have microphones and other sensors, so it'll be hard to be sure you're not being recorded even when talking to friends in their living room.

[1] http://www.popularmechanics.com/technology/gadgets/a24616/sa...