If you buy the 'wi-fi + cellular' version (and then fork out for a monthly subscription to a mobile phone company) you'll have internet access [on a screen bigger than you'd get on a mobile phone] wherever you go. If you buy the cheaper 'wi-fi only' version, you'll have an excellent excuse for seeking out Wetherspoon's pubs, so that you can make use of their free wi-fi ;-)
You'll also have a reasonable quality camera readily to hand wherever you go. (Having said that, I recently paid just £60 for a really nice tablet. The only downside to its specification was that the camera only offered a low resolution but I decided that I wasn't bothered because I usually carry a decent camera with me anyway).
You'll also have a device that can play all of your MP3 music files (to save you carrying a separate MP3 player). It can also play games, videos and do the basic functions of a laptop computer. (While it might be handy for quick note-taking, I wouldn't recommend writing a novel on it; the virtual keyboard would be too awkward).
Whether a tablet would be of use to you really depends upon:
(a) what you might want to do with it ; and
(b) what other devices you already carry (such as a mobile phone) that can already carry out those tasks.
Whether you actually need an
iPad (rather than a different brand of tablet) depends upon whether you think that it's worth paying extra for having Apple's operating system (or just to be 'fashionable'). Tablets running the Android operating system are cheaper and don't tie you in to just one manufacturer's system.
http://store.apple.com/uk/buy-ipad/ipad-mini