I have an iphone 4s and a macbook pro.should i get the new iPad?

I have a 64GB iPhone 4s, i use it all the time.
i have a macbook pro for school and work.
i think an iPad would be awesome to have but i don't know if i would use it enough. I don't want it to sit around after a few months and be a waste of money. What legitimate reason should i have to purchase one?

You can surf the Internet on the on with iPad. So you can think of buying one.