British vs. American words - to choose?

For a while now I have mulling over the spelling of 'color'. Not about the spelling per say but whether I should stick to using the Br. spelling I was brought up with (colour) or to stick to the blogger dictionary friendly one (color).

Don't even get me started on spelling jewellery.

This train of thought eventually led to a google search of American vs. British words - different uses and spellings.

Here are a few notable ones (it's strange to think I have been using both forms of spelling for a while now):

That thingy you wear to bed
American - pajamas
British - pyjamas

This is in the mail
American - check
British - cheque

Note: I remember being told off by me mom when I first used the US version of this word; I recall having to show her the word in a dictionary to assure her that I had not forgotten how to spell ( her words; such faith hey? ).

Being good at something
American - skillful
British - skilful


Check out this site - there are plenty more spelling differences.

Question is, do I stick to British spelling or do I adopt the American spelling?

There is a case to be made for language imperialism and on the other hand, there are so many varieties of English that this arguement seems so trivial.