Fall 95 enter freshman year and we had Indys and IBM RS6000s as the main workstations on campus. Really great setup where you could sit at any workstation and all your stuff just worked and your whole environment seamlessly migrated. The only thing you had to do was if you were compiling your own stuff you'd have to recompile it for the machine you sat down at.
SGI brought a demo truck to campus in the spring of my Freshman year (Spring 96) and blew us all away. They were there for interviews, obviously I was a freshman but we all went to check it out.
Summer 96 I get an internship and for kicks they gave me an Indy with a 21" CRT (huge at the time) and the silly video camera that was like 10+ years ahead of it's time.
Fall 96 we got labs full of O2s.
Fall 1997 I bought a 3DFX card. MS/Intel somehow made a donation to the school and got them to start phasing out the Unix workstations. The windows NT setup was terrible, they never had the printing and seamless movement of files down till after I graduated. Video games in the Fall of 1997 on the 3DFX were basically as impressive as the demos on the $100k refrigerator sized machine SGI showed in 1995.
Probably fall 1998 I remember my Dad got a computer with an Nvidia Riva 128.
Spring 99 I graduated and that fall I rebuilt my PC with a Geforce 256.
I'm not sure when I last saw an SGI, but I did briefly use one of their NT machines IIRC.
Last time I had a Sun machine at work was probably 2004. I remember maybe 2007-2008 at work deciding for the first time we were going to support Linux, then by 2010-11 we had dropped support for Sun.
Most of the commercial Unix workstations had tons of Unix annoyances I never found Linux to have. Irix was maybe the best. HP-UX was super annoying I remember. I didn't use DEC Unix and Tru64 much. Closed source PC Unix like SCO I remember being horrible.