In SharePoint 2010, if you add a new page called "Home" (Home.aspx for the real file name) to your website, it automatically becomes the default home page of your "SitePages" directory. If you open the URL "http://yoursite/SitePages", it will lead to the new home page "Home.aspx".
If you intended to hide the original default page "http://yoursite/SitePages/Forms/AllPages.aspx", this is fine, of course. You just have to remember that it breaks the link "Site Pages" on the "All Site Content" page, or anywhere else for that matter. When you click on "Site Pages", instead of showing your site pages, it will now hop over to your "Home.aspx".