If you're the type who will like to tinker with your site, WordPress is unmatched. Get hosting, install it and start exploring its incredible ecosystem of themes and plugins.
IMO if you want a hosted solution go with Tumblr, if you want a self-hosted solution go with WordPress (www.wordpress.org, not .com).
You can customise a Tumblr blog quite a lot and you have the added benefit of not needing to worry about bandwidth (should you strike it lucky and land on the first page of Digg). For greater customisation though (i.e. do basically whatever you want) you should go with WordPress (by far the most popular blogging solution on the Internet).