META tag question for keyword optimisation

[tokyotokyo22]

If I am keyword optimising a web page for a specific phrase like "big green widgets" what is the best way to write my META keywords tag?

like this

<meta name="keywords" content="big green widgets">

or

<meta name="keywords" content="big, green, widgets">

or

<meta name="keywords" content="big green widgets, big, green, widgets">

Or does it not really make a difference?

[edited by: mona at 4:16 pm (utc) on July 4, 2007]
[edit reason] no specific keywords - thx! [/edit]

[cupcakes]

Most engines totally ignore the meta keywords tag (due to years of abuse) - I wouldn't worry about trying to optimize it.

[tokyotokyo22]

Well MSN and Yahoo still use them so I would be inclined to use them as it only takes seconds to write a meta tag.