Help me choosing materials/components for my robot

Hello, i need to make a two wheel self balancing robot , like this one: .

I need help about components:

1) about microprocessor i saw Arduino UNO and Ardquino NANO ,nano is more expensive, there is real difference about this two controllers???

2) Gyroscope i have already - ADXRS610Z

3) Accelerometer i have already - LIS3LV02DL or ADXL345

4) Motors - there is my real problems, i dont know much about motors , wich motors u advise me with wich caracteristics?

And i will need encoders and motor drives right?? Can you explain me what encoders and drives do??

So my real questions:
What u think about gyroscope and accelerometer for my robot?
Can u giveme a lights about robotic motors,so i wont make wrong buy's ?

Thank you,

I believe a Nano is smaller,

I believe a Nano is smaller, go with the Arduino. Unless size is an issue then it’d be better to spend less money.

As for motors, I’d start off with some continuous rotation servo motors, like I did. That way you don’t need motor drivers, which basically allow you control the speed and direction of a DC motor. Servos already have control circuitry built in, making them very easy to use. However, most are designed for hobby RC use, and only rotate 180 degrees. You have to modify a standard one or make sure you’re using servos designed for continuous rotation if you plan to use them for drive motors.

Encoders help you determine how many rotations a wheel has spun. For a basic “start-here” type robot, they are unnecessary, but if you wish to do mapping or precise movements, then you should look into them.

Hope I helped!