Idea A)
There is a block in the market place called page redirect. This way you can automatically redirect from your home page to your blog page for example. But after this your site URL will still look like this:
http://www.yourdomain.org/blog

Idea B)
Add your blog index pagelist directly to your homepage. All you need to do than is to setup this paglist block to list the right blog post pages, thats it. Additionally you can change the name of the "home" page to "blog" if you like. One way to do this is: dashboard -> sitemap-> click on the page "home" -> properties -> change the name to what ever you want

Oops, I started writing my response before you posted yours... well I guess these are the solutions since we said the same exact thing!

I don't think there is a way to denote some other page of the site as the home page, but what you can do is make it so the blocks on the blog page are on the home page instead -- so you're changing your home page to a blog page instead of changing the blog page to a home page.

Or you could set the home page to redirect to the blog page (using this free addon:http://www.concrete5.org/marketplace/addons/page-redirect/... ), but that probably won't be ideal because then your home page url is going to be domain.com/blog.