A beautiful recent purchase is the Library of America's American Earth: a cornucopia (1000 pages) of writing about the environment, the American wilderness, and the future of the planet. Any anthology which includes both Rachel Carson and Robert Crumb is doing something right, and this thing is gorgeous.
It has a dustjacket (designed by the wondrously named Roberto de Vicq de Cumptich) which does not quite cover the boards beneath, letting you know that there is something more going on under there.
And there is.
(Click for bigger versions of both.)
The painting is 'A Lake Twilight' by landscape artist Sanford Robinson Gifford, and is exactly right for the book: the human element in the painting is right to the forefront, and yet dwarfed by the natural world around it.
Roberto de Vicq de Cumptich has designed a lot of other beautiful covers, shown to good effect at his website. I could post dozens of them, but I'll limit myself to his picture book, Bembo's Zoo.
This book is a work of design genius. An alphabet book, with an animal for each letter, is a straightforward idea. However, this book constructs each animal entirely from the letter forms in its name, using only the Bembo typeface. As an example, here are B for Bison and P for Peacock.
An elegant (and noisy) website promoting the book also features animations for each illustration, showing how the animals were constructed.