I believe this is the first time I've actually asked for information from the masses. Initially this is an opinion poll because onions have such dynamic compositions based on region of growth, variety, size, age, storage (cold vs. room temperature); and flavor-delivery based on preparation (number of outer layers removed, cut long and thin, diced, sautéed, sweated, etc.). I'm mostly interested in what variety people prefer topping their pizzas with. The common varieties being yellow, white, red, sweet (Vidalia, Imperial, Walla Walla, Maui), and occasionally wild onions found growing in the yard or by the side of the road. I also wonder if anybody orders their onions to be shipped from a remote location.
I almost never use white onions on pizza, and a little more often I might use yellow, but most of the time I switch between red and sweet. I can only guess that I have a subconscience rule about using red with a pizza topped with meat and sweet with vegetable pizzas, because I don't feel like I make the decision consciously. If anything, the only thing that I'm consciously thinking about is the quality of the various onions on display. With so many other toppings that exhibit only slight variations in flavor, the onion really stands out as a make-or-break topping. I've had onions that tasted good enough to eat like an apple, but also others that have unstitched my socks they were so pungent. I've never experienced another topping with so much range.
So the main question is, what variety of onion do you prefer on your pizza? Feel free to include any other information about your onion acquisition, preparation, or anecdotes.
(From time to time I may come back to this thread to address the objective qualities of onions.)