Stack Exchange is the best (and one of very few useful) question-and-answer websites in the world.
In this statement, should it be website (where “best” overrules “one of very few”) or websites (where “one of very few” overrules “best”? What is the correct way to phrase the intent of this statement in a single sentence?
Update: one of my friends noted that the question is wrong. Since there is an ‘and’ within the brackets, the statement is itself a compound sentence, and hence is not reducible to a simple statement. I think he is right.
Stack Exchange is the best of the few useful question-and-answer websites on the internet.
If you are referring or comparing a thing to something similar (of the few) then the plural (websites) is required.
If you are being specific about just one thing then;
Stack Exchange is the best question-and-answer website on the internet.
This could be the best answer you get.
This could be the worst of all the answers you get.