I know this has been touched on before, and often the answer is "Dont go with a free service, get your own hosting and use Wordpress"
BUT
If you cant afford hosting, then what is the very best free blogging service? and why?

Wordpress has a free service that I've heard nothing but good about.

I have used the Wordpress free service and can certainly vouch for it i have also used Blogger which a lot of people like due to it being so easy to use.

I've been using Blogger for over two years for my personal blog, and I highly recommend them. Blogger provides an easy-to-use services and some free templates to choose from. However, if you're looking for a better selection of free templates, you can always search the Web for "free blogger templates" (leave the quotes around the keyword phrase to narrow the results).

I have blogger and wordpress blogs. Blogger have many templates you can choose from, wordpress, if free, is limited. You can also put Google Adsense in blogger, but not in wordpress. But you are indexed easily using wordpress than blogger. That's what I have observed.

hmm, use blogger if you want to put an AdSense and it has lots of templates to choose from.

I think blogger.com and blogspot.com are now the same thing. But as other people said it's a pretty good service. Somewhat limited, but very easy to use.

From the ease of use to the ability to modify your template and being given the opportunity to monetize a blog-it has to go to Blogger.

WordPress bar none. Though with the price of hosting out there, I'd still say go with that.

I hear awesome things about Blogger, but to me, WordPress is the most comprehensive

If you are planning to make revenue out of your blog, do not use wordpress since they dont allow javascript codes on the widgets (adsense is a script code). And if you want to change the domain name of your wordpress blog to yourname.com instead of the standard yourname.wordpress.com, you have to pay too.
Whereas if you use blogger, you can add any script code you want and you won't have to pay anything to change your blog's URL.

www.5starblog.com offers free blogs with over 30+ templates

Go for wordpress and you won;t go wrong...