RM
When I started at my local college, they had RM Nimbus machines in the computer room and library. It turned out that they signed a 10 year contract with RM to supply them with computers and RM did just that, they gave them the Nimbus for 10 years!
The Nimbus had a hidden feature in regards to colour, if you knew how to exploit it you could get 16 colours on the CGA monitor at any one time. This is something not even Microsoft could work out.
I actually visited RM's Oxford HQ to get a copy of Windows 3.0 for the college at one point, since they had Windows 2.0.
You would have thought the college learnt its lesson but signed a 10 year contract with Western Systems for their next computer suite (the company mysteriously went bust shortly after)