Keyword domain names still good?

Hi guys

This is my first post here after some lurking, so apologies if I'm posted in the wrong place. If so, please let me know.

I have a web-based business and am about to extend to a slightly different area of the market, targetting specific keywords. This is not particularly niche and competion is relativley strong.

My question to you experts is:

My first website domain is my business brand name which is SEO'd and has a link-building campaign ongoing which has taken time, but is paying off gradually.

My new site will trade under the same business, but as a new site supplying only the UK. I want to encompass my main keyword "electric widget" in the domain name that I buy in order to get to page 1 quicker and easier, and to show some authority. The domain name needs to be the name of my site also. Obviously, I'll ensure content is original and good quality etc.

Here's the problem:

"electricwidget.co.uk" and it's various permutations are taken, so what are my alternatives, does google favour hyphens, and does the word before or after the keyword directly affect relevence, even if it is just "the"?

Which of these alternatives would you say is best in the eyes of google, and any other suggestions you can make would be fantastic!

"electricwidgetstore.co.uk"
"electric-widget-store.co.uk"
"electricwidgetexpert.co.uk"
"electric-widget-expert.co.uk"
"theelectricwidgetexpert.co.uk"
"the-electric-widget-expert.co.uk"

Please, if you have any thoughts or experience on this, I'd love to hear them.