The topic is sports commentary.
The purprose, hmm... Haven`t really thought of one yet. It`s just a hobby thing for now, though I eventually plan on adding features and turning it into a bigger site; a blog seems like a good starting point.
Wordpress.com is just a hosted implementation of the Wordpress software, correct? What are the benefits of a stand-alone implementation over a hosted one?
Nope, it will be sports commentary, more specifically mixed martial arts & UFC. Nothing to do with web tools or technology.
I`m still undecided on whether to go with a hosted solution or a standalone one. I am leaning towards hosted at this point. I want something that can be set up quickly, and it also seems like hosted blogs have the benefit of additional visibility from the parent site. If I want to add features in the future, I can always move to a stand-alone website later.
Wordpress.com actually seems nice! I will look into Terapad.com as well, thanks for the pointer Andy. I already ruled out Blogger.com (formerly Blogspot), as soon as I realized that it requires a Google account... 
I`m a big fan of WordPress. It`s easy to customize, has the Pages feature which allows you to create pages that aren`t part of your blog and lots of plugins to extend the functionality.
Hosting your own wordpress installation allows you to customize more. There are many more options for plugins and themes that wordpress.com will give you. Also, if you have yourownname.com you have to pay to point it to your wordpress.com blog. Why do that when you can have your own site?
Good luck!