Should I get the iPad if I already have the iPhone?

I have the iPhone 5, and I'm fascinated by the iPad's large screen… I don't have a laptop or computer. Would this be a good fit as a laptop/computer? I love my iPhone and don't want to abandon it though! Lol.

Can someone who has both explain to me if it was worth it?

Also, I plan to use the iPad for apps, videos, movies, and surfing the web.

I asked this before and people seemed 50/50