There is a large and ever-growing variation in screen sizes in the marketplace today as different sized mobile devices come onto the market as well as bigger and bigger screens such as 50" plasmas.
The 960 Grid System
Our designs are based on the widely accepted 960 pixel grid system which was created to help web companies handle the growing difference in screen sizes and allow a good user experience.
This means our web sites render well for the majority of devices in use including standard desktops, laptops, mobile devices such as iPads, and also smaller devices like the iPhone. These devices typically allow you to pinch and resize for better viewing and users can complete the checkout process as normal. We normally recommend designs have background images up to 2000px in width which typically handles the bigger screens available today.
Responsive Design Versus 960 Grid System
Responsive design allows web sites to adapt the size and layout of images and page content as the screen being used changes in size. There is a cost premium to develop responsive designs as the amount of graphic design work required to create this can multiply up the price 3-fold. This tends to makes it unattractive from an ROI perspective as most people still search/buy off standard devices and iPad size mobiles, which the 960 grid system will handle.