Re: Favourite thing about new operating systems..
I think you should be focussing on the fundamentals, like the PID and RAD algorithms as well as the invocation of safe states.
Also, disk scheduling algorithms are important, as are the implementation of mutexes, semaphores, monitors and other concurrency concepts, as well as the correct handling of critical sections.
I feel that eye-candy is all good but if the cake underneath is undercooked the whole thing falls over and is generally poop.
Master of common sense. If you don't like it, stop reading.