The HP-67 seems out of this world
I've always wanted one of these. Today a very kind person sent me what was needed to fire this machine up. The HP-67 was a powerful programmable calculator/computer, which could read and write strips of magnetic cards to load programs in 1976. Out of all the classic HP calculators, the HP-67 stuck out for me - the ambition in its input/output, and the beautiful key colours which have become emblemic of HP's peak (I'm assuming Calculator Clique felt similarly). The 15 digit LED display is also remarkably crisp and the digits look sharper than modern LCDs.
On the other hand, while this is in some ways my 'grail' calculator, it's also not one I'd use day to day. The keyboard is heavily overloaded with functions, and most keys relate to its programming ability. Hugely powerful, but maybe not so great as a general-use calculator.
PS Photographed on a Nikon Df, Micro-Nikkor 55mm at f16 on glass with real clouds present. The display is not so clear, even in the shade in fact, but it's pretty bright indoors. I may wait for the sun to go down and see if I can get a clearer shot of the LEDs. I also added a photo of its predecessor, the HP-65, being used to calculate course correction times for Apollo-Soyuz mission.