These days I digitize them (or buy them pre-digitized if I can get them without DRM). That is because a large portion of the books I buy and keep are nominally "reference" works rather than fiction. The reading experience is certainly different but with screens not horribly so and everything fits on a couple of flash drives so no risk of having my library burn up or get buried in an earthquake.
My archival format is this hi-res color PDF (sadly, I like the yellowed color of old pages and like to have that retained when reading on an iPad.) These files are quite large (100 meg or so). Lucky enormous hard disks are cheap.
For daily reading, I send the PDF's through an epub converter that turns them to lower res, B&W epubs and then onto a Kindle Paperwhite.
I used to be bothered by the destruction of the book, but now its almost spiritual. The book must go through the ritual and give up its corporeal form so that it can live forever in my digital Valhalla.
Did that for about 6 months and processed a bit more than 60,000 pages. I bought a nice guillotine cutter off Amazon and a ScanSnap 1500 scanner [3]. For a lot of paperback references I could cut the spine off, drop it into the scanner, and it takes less than minute to scan the entire book, both sides of the page. I also scanned a several years of Scientific American, Nature: Materials, and other magazines I've kept for reference. Yes it "destroys" the book, generally though I'm ok with that. If I really want something in book form I'll buy two copies, scan one and keep the other. For reference material it is much more helpful to have things digitized. I've been working on a home grown data management application which catalogs and cross references information from the books. The whole library is less than a terabyte at the moment.
[1] 1dollarscan platinum membership -- http://1dollarscan.com/membership.php
[2] Stack S12 guillotine cutter -- http://www.amazon.com/dp/B000YI5P76/
[3] ScanSnap 1500 scanner (current model iX500) -- http://www.fujitsu.com/us/products/computing/peripheral/scan...
My entire library is archived in AWS' Glacier, and costs me ~$1.50/month to store.
I was thinking getting an iPad so that the resolution is tolerable vs actual books.
Everyone's definition of "quality" varies, but this has worked well for me for the past 2-odd years; undoubtedly there are better tablets, but the Nook HD+ struck a cost/benefit sweet spot for me. If my Nook HD+ broke tomorrow I'd probably replace it with a 1080p Lenovo Tab2 A10 tablet for 180USD.
[1] http://pro.sony.com/bbsc/ssr/show-digitalpaper/resource.solu...
I, too, used to dream of having a big home library. Now I dream of a home with almost nothing in it. (If it weren't for music scores, which I use at the piano, there wouldn't be any books in the house other than what I'm currently reading and hasn't been scanned yet.)
But the fact is, if I'm retaining a copy of the book (with my scan), I can't give the book away. I still have it. That would be stealing. It is really disheartening to see people here on Hacker News who believe that intellectual property should be stolen and/or has no value. That's disturbing.
I now have a library in my house (not builtin, but 84" shelves nearly wall-to-wall. It's nice :)