1976 - used HP 3000 Minicomputer, don't remember OS.
1984 - DOS 2.1 - This was the first OS I purchased.
1985 - DOS 3.1
Eventually also used DOS 4.x, DOS 5.x but don't remember dates
1985-present - Tried Windows 1.0, thought it was useless but eventually used every version of Windows including NT and Server editions.
1986-1996 - IBM VM and MVS on IBM mainframes
1989 - AmigaDOS 2.x?
1987-1999 used various versions of OS/2. Started as a Beta tester pre 1.0, used thru Warp 4
1996 - IBM i on AS/400
2003 - Sun Solaris
2009 - Mac OS X Leopard and Snow Leopard
Present - I have machines running XP, Vista, Win 7 and Win 8 as well as several running Linux distros
I'm sure there's others I've forgotten. I've been a programmer/software engineer for almost 30 years so had to use/learn many OSes.