ElegantThemes provides Premium WordPress Themes that come in valid XHTML and CSS. All of the themes are upgraded for the most recent WordPress version. I have been a satisfied customer for over year and the support is amazing as well.
ElegantThemes offers dozens Premium WordPress Themes that you can download all just for one-time fee of $39 for membership. As a member you get access to all themes along with upcoming new themes as well. It’s worth it!