wiring the Avcc pin to the Vref pin is both redundant and a bear trap waiting
Good call, retrolefty.
By AVcc I was actually referring to an external supply circuit created for supplying the ADC reference and the sensor, ("The very best solution it to create an analogue supple, AVcc."), feeding the reference of an external ADC, not the AVcc pin on the ATmega328P. But you're right, my ambiguity could easily lead some people astray. So, if you want to use this method with the Arduino's ATmega328P, by all means connect the AVcc circuit to the AVcc pin on the MCU, and select this as your ADC reference.
With this in mind, I'm going to edit that post to remove the bear-trap. 