A slightly different perspective, written from an iPad.
For me it’s a fantastic sofa/ living room device: always on, straight into looking something up or checking social networks and STW. Lovely to surf the interwebz with. Massively prefer it to my MacBook and iPhone now.
The one I’m using is a work one and though we’re cliched media types, none of us have really taken to it for proper work stuff. If I’m really trying to *do* something online – bookings, buying, registering, interacting – I find myself quickly frustrated.
So my feeling is that it’s a fantastic luxury to have for idle browsing and funtimes in an increasingly online world; for me, not so much of a proper work tool.
With that in mind, I wouldn’t personally bother with 3G given the likelihood of being somewhere known, and then just get whichever storage option you can afford but not worry about it too much as most of the content – in my mode – will be hosted online.
Hope that helps and enjoy 🙂