I was also a little surprised at the low ranking for Charles de Gaulle; then I started perusing comments about the airport on the SleepingInAirports site and noticed phrases like "really rank smells" and I wondered if we'd visited the same airport?
What are my favorite airports? Actually I have a bunch, but remember, you're hearing this from a guy who doesn't check a bag ("there are two kinds of bags, 'lost' and 'carryon'"), so I believe in taking some personal responsibility for one's airport experience. It shouldn't have to be that way, but it is.
Beyond that, well – it would be fun to avail oneself of some of the services offered by Singapore's Changi, like the massages and the swimming pool; and I would enjoy the multi-media lounges at the Hong Kong airport, with the free WiFi – but, I am a simple man with simple needs.
For me, the best airport is one where my plane arrives and departs on time; it is a facility that prides itself on cleanliness; and is easily navigated by all passengers. It doesn't seem like much to ask, does it?