What are some geometry books with particularly beautiful diagrams? Old or new. Could be on 'standard' material or specialised on one particular topic. Something for the connoisseur of mathematical beauty in all of us to savour.
The book by Fomenko, Fuchs http://www.math.columbia.edu/~khovanov/algtop2013/Fuchs1.pdf has amazing pictures by one of the authors. Pictures are a bit surreal, but there are explanations of the illustrations. I really love this book!
Please see the MO question, "Are there other nice math books close to the style of Tristan Needham?", which I feel pretty much answers your question.
I would definitely suggest you take a look at George Francis' book A Topological Picturebook. It is full of beautiful and intricate drawings of surfaces and whatnot. I have never really read the book, but ever since I first looked at the book in my university library, I can't help but glance through it every time I see it on shelves just to take a look at those beautiful pictures.
Probably one of the most fabulous is the fractal geometry of nature by Mandelbrot.