"it more logical to simply select the most widely used form of English in the world. According to Wikipedia 67.2 % of the worlds first language native English speakers are in the United States, the United Kingdom has 16.9 %, and Canada has 5.8 %."
As I told you, I do not think this is logical. What matters is not the numbers of people who speak it. What matters is that actually everybody understands it.
The original Latin was spoken only by a very few people, mostly educated ones. The "common" latin was very different from the "original" one, and was even more different depending on regions. But when you wanted all these different regions to comunicate fluently with each other, they used the "original" one, even though it is not spoken by the majority.
I know that all English "languages" are not very different from each other. So this discussion is a bit silly anyway. But you have to see I come from a country that spread a languange all over the world, and it is very difficult to actually understand each portuguese dialect. There are 10 million in the original Portuguese country, but Portuguese is (or at least was last time I saw these kind of statistcs) the 6th most spoken language in the world. Still, it is more common to see the Portuguese from Portugal in books and games instead of the Brazillian one, even though they have 10 million just in the capital city...

I don't see using the UK english as a sign of Imperialism, but more as a sign of respect to all english speakers out there.

But don't get mad with such little things! The only way to get over this is to invent a time machine and kick the ass of the architect who design the Babel tower!
