I prefer hardcover for comicbooks but I settle for paperback if it's the only option.
For regular books I prefer paperbacks.

Unfortunately because of the price that's very often not the question, but for specialised literature which you need frequently I would prefer hardcover, because it feels more robust. For novels you maybe read max 2-3 in a lifetime paperback is better, because it's cheaper, takes less space in the shelf and it's more handy for reading on the road. Lately I read more on the tablet (mostly classic stuff from the gutenberg project), which is quite enjoyable and already a good substitute for novels, but for specialised literature I still would prefer a well printed book.

Hardcover for valuable/important books and e-book for all else.

Personally, I prefer hardcover, as they tend to last longer than paperbacks without any damage.

Financially, though, I probably buy more paperbacks given that hardcover prices are generally so much higher (unless I find cheap bargains online!)

Comparing real books to ebooks -- I prefer real books as ebooks, for some stupid reason, incur V.A.T. costs, whereas real books don't, .

I prefer kindle. I don't have shelf space for books, nor do I like the weight. I switched to ebooks back in the PocketPC days and I never want to go back to paper.

I prefer hardcover for those books I intend to keep, especially for art books (of which I have many). For portable or non-repeated reading, ebooks are hard to beat for convenience. Paperbacks are only a choice for me if that's the only version in print, or if I'm planning on taking it with me somewhere that getting to an electrical outlet is an unreliable factor.

Ebooks. Since I've gone all digital on games I just can't bear to buy a physical book anymore, just something about the fact that it can degrade and thus isn't "forever" like an ebook gets at me.

Ebooks, normally. If not ebooks, it depends; if it's something I'm likely to read once and then give away and not think about again ["Because the local library is shit," to answer the obvious question], then obviously "cheap" is the main thing I'm looking for. If it's something I might still have with me a decade later, hardcover.

Hardcover. I'm usually a digital/non-physical guy but something about books I like to be genuine and high quality but I don't mind e-books, I've used a few on an Android Tablet and it's a very welcome convenience (changing letter size, font and brightness is important to me).

In the future maybe tablets can change their materials to look and feel like books made of paper, could be something.

Hardcover, its more reliable.
Good luck with long term preservation value, what happens if kindle shuts down.

My ereader allows for the writing of notes in a book so assuming that the book is DRM-free, you could get the author to sign it.

This is for select ereaders and select books though.

Hardcover.

When I when ebook, I mean PDF.

There are numerous ways to convert from Kindle's format into other ones.

What do you mean long term? The paper which is used in modern books will not last anyway, no matter what cover you have.

For me, it all comes down to book's volume. It's not that comfortable to read a 1000+ pages book with hardcover. At least not for me.