When anyone talks about the 'best' anything it's subjective. Having said that I have traveled all over the USA, Australia, New Zealand, Canada, Central/South America and Europe. One of the best I have ever eaten is in Iceland. It was referred to me by the owner of the local Harley Davidson shop. It's a little hard to find, walkable from anywhere in the city, depending on weather. I have no clue how to pronounce it but here is name and address:
The menu is in Icelandic and English, and the staff like all of Iceland speaks English as well as anyone. It does get very busy on Friday and Saturday evenings. They have all the basic toppings plus a few local things. It may sound strange but they offer cream cheese as one of the toppings, which I recommend. All pizza baked in a real wood fired oven. Prices relative to Iceland are very reasonable.