Some people are incredibly hard to buy for. But, nobody is impossible. The trick is really to listen all year long. Clues are all around and every once in a while even the most difficult person will say or do something that will give you an idea.
Just keep your ears open and your eyes peeled. Fill a need, be it ego, emotional, or physical.
At the end of the day, even a toaster might end up being a good idea. You just have to really listen.