The first PC in my home was an IBM XT, that I got for my 9th or 10th birthday, (I don't remember which) back in the early '90s. I was learning programming in BASIC and DOS on Apple IIe's in grade school at the time, I wanted a computer to play around on of my own, and the XT was what my mom found me for what she could afford at the time.
It came with one 5.25″ floppy drive and a 10MB hard drive, and with three disks: One boot disk, one disk with the games Wheel Of Fortune and Golf, and one with an early version of Microsoft Word.
I used it, even after having newer systems in the house that everyone else used, until it finally died when the motherboard crapped out on it. The thing lasted, in my hands, almost 10 years, and that was after it was already about 10 years old when I got it. Too bad PCs just aren't built as well anymore.
I wrote programs in Fortran and in 360 assembler. I'd stand in line to submit a stack of punch cards to a computer operator at the University of Toronto. Hours later, I'd pick up the resulting printout (from a noisy IBM line printer) which I then had to burst.
I still have the 360 Assembly Language manual somewhere. White and orange cover, as I recall.
After that (at grad school), I programmed Conroy's "Life" automaton in assembler on a PDP-1. Those were the days.
My first PC was an Amstrad 1640. Intel 8086 processor @8mhz, 512Kb RAM, MDA display and lo! a luxurious 20Mb HD! With MS DOS 3.3. And of course no sound except for the pitiful beeper. I was less than impressed I must say, since I already owned an Atari ST and knew the Amiga platform and they where much nicer. Yes it was an outdated machine. Anyway, that's the computer with which I discovered Rogue and this, this has no price!
*coughs ashamedly* A PC jr, in about 1986 or thereabouts, from memory, and an Epson clone to boot. I believe my response at the time was, "You sold my Commodore 64 for THAT?!?" I learned most of the DOS commands, but it kind of turned me off computing until I got a 286, wherein I got back into gaming and programming soon after.
As far as real (branded) IBMs go, probably the RS6000 about 10 years ago. Now that was a sexy piece of computing hardware.
Ah, the ole PCjr. I think I was about 14 when we got one in the mid-80s, and I had a lot of fun with it. From the great graphics in King's Quest, to installing the sidecar 300 baud modem that allowed me to literally read along with the text as it downloaded/displayed during my free trial of CompuServe (first order of business for a teenage boy? The 'Adult Dictionary' of course).
My family's first PC (in the modern sense, not first home computer) was an IBM DX2 50MHz desktop that my mother bought in '94 for $2,500 after getting a very nice inheritance. My brother and I insisted on a PC because a little shiny postcard from Origin Systems said we'd need it to play Ultima 8 — happily, my Apple-fanatic stepjerk was so ticked that he moved out pretty much for good in protest!
I also had the fun experience of taking a hacksaw to the case because the SCSI-to-parallel adapter we'd gotten was too thick to pass through any existing opening. Never try to run an internal 1GB SCSI Jaz drive through a parallel port, it was painfully slow even for back then…
The earliest IBM computer I used (that I know of, I may have used an older mainframe once or twice) was an IBM 5160 XT with MDA monitor I got at a Goodwill store for $40. Sadly, my brother (who is 4 years older) was jealous and ruined the system a few days later. I remember the hard time I had carrying it home for 1 1/2 miles…
At Lenape Vo-Tech in Ford City, PA, I had the privilege of using an IBM 360 via its dumb terminals and via terminal emulation on the IBM 5150 from '89-'91. The mainframe was used mainly for school administration and for teaching how to program in COBOL and RPG.
There were a couple old IBM 5150′s and PS/2 model 25 and 30 systems. The teacher's "workhorse" PS/2 was an 80286 PS/2 with a grayscale flatbed scanner, Windows/286 and Aldus PageMaker. Yet, for some dumb reason, the scanner was mainly used to just "photocopy" to the laser printer and the printouts were cut by hand for newsletter layout work. Needless to say that I was far more adept at using PageMaker for my own projects.
The teacher wasn't too bright and I hung out with a couple other hobbyists where I found myself in the middle of lots of software trading and assisting with sysadmin work.
The 360 was a beast! Think of a clotheswasher but on steroids. That was the main system with a huge honkin' printer near it which could have doubled as a clothesdryer. The technology there was a washout, to say the least. It was as if the Vo-Tech got the IBM hand-me-downs from the local businesses.
Up to that time the oldest computer I've used was my cousin's TRS-80 Color Computer that got me started with this huge computing bug back in '79 or so.
XT, Hercules graphics card, green screen. I'm not sure if I had a 40MB MFM/RLL hard disk back then, but probably.
It was great, booting up into a speciall prepared DOS shell that taught you how to use it as you went along. It was only a short amount of time until I worked out how to make my own menu systems to do what I wanted to do, and then get rid of them entirely so I could just sit at the prompt. I was only 11!
Every week I participate in the IBM 1401 Restoration Group at the Computer History Museum in Mountain View, CA. (http://ibm-1401.info/) The machines there were built in 1961 and 1864. I data processing is included, the oldest thing I worked on myself was the 513 Reproducing punch (http://tinyurl.com/434m7mn).