I have tons of older systems, the oldest of which is a
Macintosh IIcx (1989)... but the oldest of my systems that is set up and in regular use would most likely be my
Quadra 950 (1992). If we are talking about
daily use, then my
PowerBook 3400c/200 (Feb. 1997) is my oldest laptop and my two
Power Macintosh 8600/300s (Aug. 1997) are my oldest desktops (with my
Power Macintosh G3 Mini Tower (Nov. 1997) following them pretty closely).
When looking at the system software they are all running, it pushes the dates forward a little for each...
Quadra 950..... Mac OS 8.1 (1998)
PowerBook 3400c..... Mac OS 8.6 (1999)
Power Macintosh 8600..... Mac OS 8.6 (1999)
Power Macintosh 8600..... Mac OS X Server 1.2 (2000)
Power Macintosh G3..... Mac OS X v10.3.9 (2003)
And Mac OS 8.1 (January 1998) just edges out Rhapsody 5.1 (May 1998) as the oldest Apple operating system that I use regularly... unless you count OPENSTEP 4.2 (which was released by Apple in January 1997). I run both Rhapsody 5.1 and (every so often) OPENSTEP 4.2 on my IBM ThinkPad 760ED and OPENSTEP 4.2 on my Sun SPARCstation 10. I haven't had a need to run OPENSTEP on my ThinkPad ever since I got FrameMaker 6 for my Mac OS 8.6 systems (I was using FrameMaker 3.2 in OPENSTEP on my ThinkPad because their wasn't a SPARC version for that app to run on my SS10).
My newest system is a
PowerMac G4 (1999) which replaced my
iMac G3 (2000) as my newest system after I retired it. The newest system in our household is my wife's
PowerBook G3 Pismo (2000), but I am hoping to be able to replace that system with a
14" iBook G3/900 (2003) for her in the next month or so.