I have one and use it as a satnav (much better than my TomTom); eReader using the Amazon Kindle app and the Google app; watch tv; browse the internet - emails, facebook, twitter, AnswerBank etc; the banking app is much better than the web online bank (depends on your bank); play games; listen to the radio; use it to quickly check the weather forecast (weather app) and news (various news apps) when I don't have time to boot the pc up; Skype is excellent on it and the webcam is good enough.
All of my documents, music, photos, videos etc are stored on an external hard drive so I can access everything on my tablet when I'm at home without clogging up the internal storage.
It is great when I'm on holiday as it is very easy to carry and when I'm in a wifi spot I download the news for later reading, catch up on emails and use Skype.
My smartphone can also be turned in to a wifi hotspot so I connect my Nexus to that if I want to access the web outside the house where there is no wifi.
Tablets are designed to be always on in the same way your mobile phone is always on which means they are very quick to use and instantly available.
There is a wide number of apps available in the Play store, some free and some that you pay for. Take your time to browse and try the ones you fancy - it is easy to uninstall them later.
I particularly like the night sky app - I can use it to identify stars very easily.