Check the article link below for a review of several options
You can certainly watch shows on computers and smartphones, but I find the iPad especially good for this purpose. It is a lighter, thinner and more immersive device than a laptop, yet it has a large enough screen and strong enough battery life to make TV viewing satisfying. It can even transmit shows, via a cable or wirelessly, to big TV screens if you like. Competing tablets also will be good platforms for this, but, so far, they have far fewer TV-watching apps, so the iPad is by far the best tablet for TV watching now.
Here is a quick guide to how to view traditional TV shows on an iPad.