Great idea for a thread. Control schemes used to be a frequently discussed topic back in the D1/D2 days, especially with older keyboards with chording issues. The pilots I used to fly with used some widely varying control schemes to work around issues like that, and to make sure they had enough free fingers to actually do everything.
My control schemes are a bit different than most because I play most games with a left-hand speedpad and use the thumb D-Pad for X/Y axis movement. I strongly recommend to anyone with a device like this (Nostromo / G13 / Tartarys / Orbweaver) that you try this out. It takes a little getting used to, but quickly feels natural and frees up a lot of keys/fingers for other actions. I've also found that creating slide key layouts that are arranged "like arrow keys" helps to map the four-directional sliding into your head-space (on my current setup I even have redundant L/R slide bindings to make this possible).
For people playing with keyboards, I also posted a picture showing the keybinds I used to use in Descent before I had a speedpad in case anyone wants to compare notes.