Sun Microsystems Ultra 10

The main computer on my office desk from the late 1990's until about 2004.
This was my go-to system when I started an engineering company after leaving
a London-Based communications company.... It was this system and a netware
server that effectively paid for my first house...!

440MHz ultrasparc IIi with big 13w3 connected monitor. and under a gig of ram.