I like to give books as holiday presents, and I got some great deals through Daedalus Books this year. They carry mostly remaindered books at incredibly low prices, and they have new titles that are pretty heavily discounted.
One of the books I got this year was Fun with Computer Electronics. It comes with a book and lots of parts – LEDs, wires, resistors, a piezo transducer, and a couple of pre-mounted chips. You build projects by connecting parts via little spring terminals on a cardboard breadboard. The book explains a lot of basic concepts like AND, OR, NAND, and XOR gates, and the whole kit is only $5.98, a great deal! They have lots more books for kids, science books, fiction, music, and DVDs, check them out.