One WordPress install for main site at domain.com and blog at blog.domain.com?
You would just need to use the multisite functionality now in WordPress, see http://codex.wordpress.org/Create_A_Network. Setup the site to use the subdomain install. You would then setup the main blog to be your site, ignoring the posts section for that site. Then setup a new site within the Super Admin menu and set the subdomain for … Read more