Oh on the kindle books, some are good and some aren't worth the bytes.
I tend to get the Kindle books that people I know recommend, or ones where they are linked from recipes posted on various sites. Even then, I usually wait until Amazon or some of the other book sites have them for free.
I haven't actually counted the number of physical cookery books I have. It's nowhere near the number you have, but it seems to be increasing regularly. I started collecting individual recipes some time back, either cut from mags and newspapers, handwritten, or just printed off the internet, and there are absolutely thousands upon thousands. Quite a few I have actually tried and others I keep for reference or to try or to adapt.
I've also got several sets of part works. The ones that belonged to my grandparents were all published in weekly parts in those days, but they are not cookery books as such. They all have "encyclopaedia" in the titles, but that definitely does not mean they are what we refer to now as encyclopaedias. Some have cookery sections, and the others have recipes throughout all the parts, and most of the recipes are for 40 or so people, so they need adapting! They were bought at a time when one of my aunts was in service in a large house. She had progressed from kitchen maid to being the maid who did or repaired all the embroidery, so these books became pretty much redundant from that point of view. However, luckily for me Grandad kept them and then passed them on to my Mum (who used to be a cook in all sorts of establishments such as dockside and other East End pubs and ended up working in Kelsey-Hayes/Ford's canteen!). I rescued them when she died - some of her cookery books had already disappeared, and I've a sneaky feeling my brother threw them away when my Dad died. I do have some other part works too from the 1970s and 1980s, one of which I use regularly.
My daughter has a collection of cookery books too, and funnily enough all of her are entirely different to mine except for one - a book which was my Mum's, which I inherited along with all the others, but I already had a copy of it. Most of my daughter's books are a lot more modern in outlook than mine - she is into Nigella Lawson and the like.