Been using a iPad 2 for around 3 years now. Like Brogan I didn't think I needed it, more or less got it to see how usable it would be in my offline business. Turns out that it ended up being extremely useful for calendar events, customer list and invoice/estimates. It was so handy, my father (73 at the time) and business partner ended up getting one and uses it daily. He always says "Why did I wait so long to get one of these!".
I didn't see the need for a tablet either until I bought my Nexus 7. Now I use it all the time, it's so much more convenient to use whilst sat on the sofa in front of the TV instead of a laptop on my knees.
I still use a laptop for work purposes and when doing admin stuff on my forums (installing add-ons, cos tweaks etc). For more 'casual' stuff I'll use my tablet.
I got an iPad Mini primarily to compliment my array of other iOS devices. its now really nothing more to me then a useful tool to troubleshoot and test forum behavior on mobile/tablet devices. I use my iPhone for just about any other mobile related activities.