standard html charset?

I'm not quite a HTML newbie but this is a newbie sort of question. Just something I haven't bothered checking out until now.

What is the standard HTML charset (you know like iso-8859-1 etc.)? The website is for an English speaking market so US, UK mostly.

There isn't really a standard charset, but most English websites use iso-8859-1 or utf-8. It's really up to you. For more info: http://www.w3.org/TR/REC-html40/charset.html

For search engine purposes which is the best?

Are there dis/advantages to either?