[profitbaron]

If you're going down the hosted route then you should use either Wordpress.com or Posterous. The reason I didn't include Tumblr in this is because, its more of a 'reblogging' type service and is different to what Wordpress/Posterous offer.

However, if you are going down the self hosted route so you can host it at blog.yourdomain.com then I'd again recommend Wordpress since its a great service, and its really easy to work with.