What's the best embedded chip there, PIC, Motorola,... in terms of price and power consumption

I think Atmel AVR series is very convenient in both operation, operation stability and cost

Depends on the requirement, in most cases pic/dspic satisfies the need, it highly equipped with many peripherals, I2C, SPI, CAN ..
you name it.
the microchip controllers family is cheaper than other products in the market.
I can't say it has the most optimized power consumption, ST and TI has better Power management.

Hello, in term of price the PIC is the best one also it has a low power consumption; for example you can see the "PIC24FJ256GB106" it has a low power (<100nA standby current) and its price is less than9 US dollar and also it's equipped with4 UART ports for establishing the bluetooth communication