I recently removed the hyphen on blog-stalk, changing the URL to http://blogstalk.com. At the moment, the old URL still has a decent search engine rank, but the new URL has a very low rank. I submitted a change of address request via Google Webmaster Tools, but this hasn't helped in any obvious way yet.
Related to this, I was experimenting with different URL structures for SEO. Google indexed my site several times while I was experimenting with different options. This has resulted in many indexed pages that have invalid links. My sitemap file has been updated, and the site seems to have been indexed again, but the bad version of the links is still in the database and the proper version is not. The URL removal tool seems to no longer exist, but help files still refer to it.