Best Tablet Size?

I am deciding between a few tablet hybrids/convertibles, I am a student and I need something that combines a tablet and a laptop. I need to be able to take notes too. I just cannot decide which size I should get. I know I have posted a few similar topics having to do with tablets, I just cannot decide… (surface pro 2 vs sony vaio flip), hopefully this will help me decide.

What size do you think is best for a tablet?