First: A 33Mhz Packard Bell with 8Mb memory (I think), 256Mb HDD, sound card, video card, and a turbo button; running Windows 3.11
Longest use: A Celeron 1Ghz (or so) desktop maxed out with 512Mb RAM, a 30GB HDD, sound card, cheap network card, and ATI Rage XL 8Mb PCI video card. Started life in 2001, was in active use up to a couple months ago [schoolwork for most of that, a stint as development / file server, then sat around for a few years, and lastly resurrected as a media player].
Latest: A Haswell Pentium 3.2 Ghz, 8Gb RAM, 500GB HDD running Ubuntu 14.04.2. viewed with a Gateway* 24" 16:9 LED IPS and a Samsung 19" 4:3 LCD. Planning to upgrade to a 256GB SSD (HDD was from a old machine) and a Nvidia GT 730 or GTX 750ti sc
* Yeah, I didn't know they were still around either!