Do I need an ebook reader?

With the recent news about Amazon's new ebook readers I got to thinking.
I love reading. Admittedly I don't get as much time as I used to but getting lost in a good book is still one of life's greatest pleasures.
The aforementioned lack of time means that there is a backlog of books to read. A couple of large volumes are awaiting my attention and there are a handful of second hand books I also would like to peruse in time.
I am hoping to catch up with these books over Christmas. A couple of flights and some sitting around in the sun should be extremely conducive to reading. But as already pointed out some of these books are large and heavy. Wouldn't it make a lot of sense to buy some form of ebook reader and read them on that?
However I have the books to read already. So using an ebook reader would involve me purchasing them yet again. Not to mention the more than eighty feet of shelf space in my house, full of books I have read and will sometimes read again.
How, also, would I share books within my family as I can with a bookcase where everyone can freely help themselves? Would it mean too, giving up browsing in second hand bookshops for books you might never have read if they had been full price? What of flicking through the pages to determine whether a book is worth buying, whether it catches the imagination in a few paragraphs or pages?
To be fair I can imagine some technical solutions to these challenges but I wonder if they will ever be implemented in a way that feels natural and easy to use.
And, anyway, sometimes it's just nice to touch the paper.