TeleMate - I might still have the original floppies somewhere. I still miss how easy this thing made file transfers; there's simply nothing like it in the modern era.

Commander Keen and Jazz Jackrabbit -- we played the hell out of these and it was only right to register them. Additional levels, whoah!

PKZip 2.04g -- back when software could just be "finished".

mIRC -- I sunk way too many hours of my life into mIRC scripts....

ACDSee 3.x -- Another "there's just nothing like it especially on linux", the fastest JPEG viewer ever to exist. I could crank up my key repeat rate, hold PgDn, and it would blast images into VRAM as fast as the keyboard asked for. Used 4DOS-style Descript.ion files and, to this day, I have a mindboggling amount of photo descriptions trapped in these files. No modern equivalent makes it so easy to tag things right in the filesystem without sucking them into some walled-garden database.