For cleaning purposes, we here at Greenway find that synthetic materials are the most durable and are the easiest to clean. Natural fibres such as wool, cotton, linen and silks are not so forgiving when you spill something on them. Leather is great and is easy to clean, however, it can be cool in colder climates.
We find synthetic blends are a good choice. They are very appealing in feel and various colour choices, and offer hard wearing capabilities. These choices should be based on your lifestyle (ie: kids, pets) and what/where you will be using the materials.
At the end of the day we CAN clean all fibres, including silk, but some materials are more durable and resistant than others.
Check out this link It may help you out with your decision: http://furniture.about.com/od/buyingfurniture/qt/pe52609ts.htm