HP 19C Calculator (1978)
This was the first scientific calculator that I ever owned, and it carried me through engineering grad school back in the days just at the dawn of the PC. It had a tiny thermal printer and a 100-register programmable memory (don't ask me how I remember this stuff) that once upon a time I actually wrote programs to help solve my operations research coursework. Now you can run linear programs from within Excel spreadsheets; such is progress. The HP line of calculators were notable for their "reverse polish notation" whereby you entered the operator (plus or times) after the number, rather than in between as most calculators require. This probably kept the HP calculators out of the mainstream, although I didn't mind the RPN.
HP 85 portable computer (1980)
This was probably my first business PC. It had a six-inch CRT screen, a cassette tape drive (that could hold a whopping 200 KB of programs!) and a small printer. The two applications that I ran back in the early 1980s were Basic and Visicalc. I built several mathematical models on this computer that were used for economic policy analysis when I worked at the Congressional Office of Technology Assessment, an agency that, alas, is no longer with us. Watching those spreadsheets load from tape was agony, but at least it beat storing them on punch cards and have the readers jam on the last card in the deck.
Compaq transportable (1983)
Also fondly called "luggable." Weighing in at nearly 30 pounds, I remember hefting this baby up into the overhead bins and hoping that it would stay there during the duration of whatever flight I was taking. This is where Compaq got its start, and differentiated itself from IBM by having all the components: floppy drives, screen, and keyboard, all in a single unit. It ran an 8086 CPU, it had 640 kilobytes of RAM, and it was a monochrome green character-only screen, but it was a beautiful machine. Compaq was one of the first companies to reverse-engineer the IBM BIOS, and I spent a great deal of time at Transamerica Occidental Life's computer support center testing them to make sure that all of our IBM software ran without any hitches on them. We had a fight on our hands when our bosses wanted to recommend the IBM portable. We knew the Compaqs were better machines. Ultimately, we prevailed -- and in time to buy them with the first 10-MB hard drives. In later years, I ran many Compaq PCs as network servers. They were just the best and most dependable PCs around.
LaserJet 5 and JetDirect Print Server (1996)
Throughout the years, I have had many HP laser printers in my personal and professional life. The most notable is the LJ5. I bought this printer for home use eight years ago, and while it doesn't get a lot of use lately, it still runs like a top, is relatively cheap to operate and performs with little attention or bother. Connecting it up to an HP JetDirect network print server has extended its usefulness, and the drivers to operate it are included in every version of Windows and Mac OS that I have connected up to it. (There is something to be said for setting up a new PC on my home network to print within a few seconds, without having to download drivers or fish around for the install CDs.) The printer is solid, with plenty of metal to bear the abuse that it has gotten being moved around, and, unlike some of the newer LaserJets, the paper path is relatively simple and the parts more durable.