You can choose any blog host that you want to use to host your blog for this class. Remember, that there are some features you want to look for, though, in order to complete your final assignment for the course. For example,
*You need to be able to categorize your posts. You can do this through "tags" on servers like LiveJournal and blogsource. Hosts such as Blogsome, Wordpress and uniblogs allow you to create multiple pages and categories with which to work. These features will allow you to separate your blog posts into readable and recognizable categories. Blogger allows you to create multiple blogs and archive your posts monthly but doesn't allow for categorization. I don't want to discourage you from using any particular host but you do need to think about the multiple features of which you'll need to make use.
*It is essential that you can blogroll your classmates' blogs as well as my blog. Most all blog hosts offer this feature either through a customizable links area or an "add link" feature or blogroll section.
*Comment features. Part of your grade is the comments you leave on your classmates' blogs. Therefore your blog needs to have comments enabled. Most of the blog hosts include this feature but you should make sure you "enable" comments so your classmates can comment on your work.
*You will want to write an "about this blog" explanation. Therefore you'll need to link to this section. Many hosts have an about feature built in or at least a way to customize the page to include one.
*Customizable templates. Since you're creating an online identity, you'll want to carry that online identity through your blog as much as possible in theme, color, images, structure, etc. Wordpress has easily customizable themes so does Blogsome as it uses many Wordpress themes.
LiveJournal allows customization in terms of color scheme and templates for free accounts, as well as many "skins" that override templates.
*Free. I don't want the blogs to cost you anything. You can often find free trials to blogs but I would encourage you not to use these because most of them are only good for 30 days and you'll need your blog for this class a lot longer.