I really like the UI design that goes into avionics - the fact that every possible scenario has to be thought out and handled, and that the end result has no flashy eyecandy or extraneous functionality; it's all function, it's all required (or it's not there); everything on the screen at any given time is significant, and (hopefully) care is taken that the amount of data (ie, significance) showing at any one moment is not information overload. A very hard balance to get right, I'm sure.
The rigor and discipline imposed over the process of software architecture and implementation in aviation (moreso than medical devices, it would seem) is both inspiring and instructive, and I definitely look up to it.
I must admit I'm genuinely interested to learn more about how the role of UI design plays into avionics construction - I've leaned toward UX for quite a while (I think I started headscratching about the subject around 13-14, although I didn't know that was what it was called at the time) and I think it's probably something I'd do pretty well at when I'm finally looking for a job. Web UX is... frustrating and demotivating, though. I don't want to kill myself doing that.