Quote Originally Posted by Moryachka
Seriously, though, they are different languages and you're not at all crazy in deciding to choose between them. .
This is the most inaccurate and misleading statement that I have ever heard of. Something that i would expect to hear from only the most self centered American.

The only thing different about the ENGLISH spoken in the USA and the ENGLISH spoken in Britain is the accent, except for what should be considered regional colloquialisms that you would find in any language.

The question you should ask yourself is "do i want an American accent or British?"
I advise going with British because you will appear more educated no matter what English speaking country you are in.
These days it is better not to be connected to America when you travel to other countries. Even in Australia, I was once berated in a Sydney pub by a rather attractive female for having spent 10 years in America. All of Americas faults were seen as mine, because I had the "audacity" to stay there so long.
You can travel much further and broader speaking British English than American.

Quote Originally Posted by pranki
Moryachka, my main goal is not to be a laughing-stock I think, it will be very funny if one phrase I speak in British and another one in American So I must know at least main differences.
No one will laugh at you for any mistake you may make. I had some friends from Iraq who spoke British English. They sounded very intelligent and educated as such. You will not be able to hide your Russian accent either way.