I have two old laptops that still get regular service, one of them a Dell Inspiron 5000E from 2003 with a P3-850, and the other a Toshiba Satellite from 2005 with a Pentium M. I upgraded the 1.6 GHz Dothan to a 2.0 model in that one, also pulled the slow HDD and replaced it with a new 160GB WD drive.
I have a Compaq Presario 1273 made in 1999 that still works fine, too. It's been upgraded from a K6-2 333 to a K6-III+ 400. Still pretty slow these days though.
As for my main rig, it gets updated every 12-18 months with a new mobo, sometimes gets a new CPU midway through. The case (Antec SX1040B), Logitech Marble Mouse, and IBM Model M keyboard are all at least 10 years old, and the monitor is a 21" CRT from about the same time period. The case started with a K6-III back in 2002, and now holds a Thuban. In between, I used a T-bird 1400@1.52, an Athlon XP 1600+ @1.81, an unlocked Applebred @2.25, a mobile Barton @2.3, an A64 @2.5, an E4300 @3.1, an Athlon II X4 620 @3.25, and a Phenom II B50 @3.5.