How important are keywords in a domain for SEO?

I'm in a bit of a dilemma now. I run a Bangkok expat website which you can find it here.

I would like to break into the Singapore market now and plan to launch an expat website in Singapore, similar to my Thailand expat website.

Unfortunately, the domain I wanted – singaporeexpats.com is taken and I've bought ads space from there before. It's ridiculous, they are charging $3,000 SGD for just a small banner on the right column. The Singapore…

How important are keywords in a domain for SEO?