What about English - AU by default - there are lots of us too.. or English - Canada.
It's not hard to install language packs and as administrator you can set by default the language you want as the installed choice.
Having said that you then need to work in localising all the third party modules you have installed or your log files will quickly fill with alert notices telling you there is no localisation files.
Because of localisation there has to be a fallback to a particular language if a module doesn't provide you your language in the installation there needs to be a fallback.
You might also like to know that Perpetual Motion and DotNetNuke, owned by Shaun Walker, are in fact in Canada, not the US. And if i look at my records of subscribers - over 55,000 in my pool of sites, the majority by huge numbers is the US. I would think the same would be for the US.
Also, even if there are non english speaking sites, with the world economies often using the $USD, it seems to fall in place to use US english.
Not that I wish it was this way - it simply is..
But you can make changes to make your installation by default be UK based. I've done this with a client site -
http://www.style.net.au/home.hardware?ctl=Register
Australia is the first choice in this installation.
Hope this sheds some light on the matter.
Nina Meiers