Focus comes in a beautiful business portfolio layout with lots of features besides its responsive design. Features include: unlimited color schemes (color wheel), 12 different backgrounds, 2 unique blog layouts, a filterable portfolio (nice for visitors) and Flex slider, multiple custom post types, and more.
Price: $35
The responsive layout means it automatically adjusts to the visitors screen size making it look great on desktop computers, tablets and smartphones.
Focus one of many WordPress Responsive Themes featured here, for the self-hosted (.org) version of WordPress (read this). Premium themes typically include support and updates.
Purchase this Theme