Responsive web design is the hottest and popular topic of discussion in design community now-a-days. As usage of tablets and mobiles phones is increasing very fast so the demand of responsive layouts are increasing too. Because responsive layouts respond according to whatever device the visitor uses. But if you don’t want to use responsive themes, you still can convert your WordPress blog into mobile format using WPTouch plugin.
So when it involves WordPress theme design, increasingly more responsive WordPress are now being launched nowadays and idea of Responsive WordPress themes is grabbing the market very quickly. So the Responsive WordPress themes are the ultimate solution for devices of varying sizes. If you have budget i would recommend to buy premium Responsive theme because those are professionally done and have more functionality but if you are looking for free ones, here is the list.
Even these Responsive WordPress Themes are of good quality and free to download. Have a look at this excellent collection!!
4. Ari WordPress Theme
5. Responsive Twenty Ten
7. Whiteboard Framework