How much do you want to store when on holiday? How important is a USB connection? Noting that you cannot connect by USB to the iPad and would need the camera adaptor for a digital camera. How portable do you want it?
You can make notes, etc on an iPad. Suggest you go into a store and play with an iPad. Then try to play with an ultrabook.
I have both a lightweight laptop and an iPad (iPad is a much more recent acquisition). I'm thinking of taking both on holiday!
I would take an iPad instead of a netbook.