Having kipped within the bounds of BZN for many years (before Albert was based in my case), the early morning crackle of a departing Funbus was a noise I grew to love, as was the reverberating bass-like boom of a slowly (sometimes very slowly!) spooling-up RB211.
The one sound I found genuinely haunting (especially on a still, misty night) was the whine of the C5, which became a scream at high power - they were plentiful during GW1 and a sound that I won't ever forget.