Update: #2.5: Yosemite Spotlight, done right!
So far, by far, my favourite new feature of Apple Mac OS X Yosemite is its far more powerful, further reaching Spotlight tool!
It was OK before, but now it is great! For anyone who is competent with a keyboard, the new Spotlight in Yosemite is a dream because it allows you to quickly get at anything and everything without even lifting your fingers off the keyboard.
This will definitely minimise disruptions to your workflow; because nothing is worse than the little things disrupting your flow when you're in the "zone".
Apple + Spacebar activates it and puts it right there front and centre. From there via quick-fire typing you can: