IBM 5140 PC Convertible
Cathode Ray Dude did a great rundown on the IBM 5140 Convertible. It was the first PC computer my dad got after the Radio Shack TRS-80 Model III and the first one that had a floppy drive. We even had the serial/parallel port and the thermal printer.
But probably the most amazing thing is that this 8088 XT, floppy based computer actually had a method to sleep and wake right where you left off. As far as we know, it was the very first instance of the technology.