For me, Fasttracker II still remains the most nostalgic, intuitive, immersive DAW ever made. Aslo, one of the best thought-out pieces of software in general.

I wrote so many tracks on it, some of which played on local FM radio and in clubs. Fondest memories circa 1996-2001.

Only many years later, Ableton managed to create another DAW that got close to FT in spirit, which is don't impede the creative flow. A DAW written by actual musicians for musicians (hail Robert Henke aka Monolake!).

And recently, Bitwig pulled another stunt and married Ableton Live's simplicity with feature richness more typical of a heavyweight DAW league, without all the inherent clutter.

P.S. This seemingly turned into some kind of advertisement, but it's just gratitude from a devoted user :)

Like mentioned FastTracker was created by people in the demoscene, also the module format fasttracker created was fairly dominant in the demoscene from maybe 1994 to 1998-1999 (when PC's were fast enough that people started moving onto streamed music via mp3 soundtracks as shown by State of Mind/Bomb).

The FT2 XM format was more powerful than the ST3 format (limited in track numbers and iirc no 16bit samples?) and less powerful than the impulse tracker IT format (virtual tracks without tying tracks to output channels), but for many demos the XM format was a sweet spot since third party IT replayers were few due to the more advanced features while XM replayers were plentiful and often powerful enough to create the music people wanted to do.

Fasttracker was coded by demoscene people though, namely members of the group Triton (later Starbreeze Studios). It has a couple of demoeffects in its about screen, and even a version of Nibbles (qbasic snake game) you can play.

And if you think Fasttracker is complicated, wait till you try Protracker...