Chris Langan is reported to have one of the highest IQ's in the world, scoring somewhere in the range 190-210. His own view on IQ is that it's important, but that your intellectual productions are more important.
I think there's some truth in that. At the end of the day (or at the end of your life, if you will), you won't care so much about your score on some test. What you'll care about is what you contributed to the world. If you can use your ultra high IQ to make a positive change, that's great. We need people like that.
If you're interested in Chris Langan's work, he claims to have a "Theory of Everything":
The Theory of Theories - Christopher Michael Langan
You can also see him in some videos on Youtube. Here's the main one (part 1 of 3):
YouTube - chris langan
So this is one example of a living person with an ultra-high IQ. There are many more that could be mentioned. A lot of people in this thread have already claimed to have IQ's well above the average, although I'm not sure whether they were professionally administrated or not. I haven't personally taken any IQ tests recently that I would consider reliable.
Whatever opinion you have of this Chris Langan or the subject of IQ generally, listening to him for a while could help answer the OP's question. I find at least some of his ideas quite interesting.
I especially like his remark that people with lower intelligence often think they're as smart as (or smarter than) the smart people (i.e. they lack "meta-cognition").