Good idea about the plugin James.
We've had a business blog -
The Better Way to Pay for a little over a month now. It's a mixture of informative business/payroll related articles and information for our customers on our products.
With only a little promotion we're now getting a healthy amount of hits through feedburner every day. It's going so well that we intend to start hosting it on our own server soon - currently it's on Blogger - as from an SEO point of view the more traffic attributed to our site the better.
And sticking with SEO; blogs are great as they're fresh content on the site, which Google likes to see. Plus you can optimize each new post to a particular key phrase that you might be targeting.