By no means will the aesthetic of your site be the only factor in your site’s success or lack of success. It is one factor among many, but given the increasing competition it only makes sense to have as much of a competitive advantage as you can.

The importance on aesthetics doesn’t mean to have a good site design you need to overdue it with the imagery or add fancy flash animation. In fact I’ll argue that other than for a few specific industries both will probably do more harm than good. What I think is important however is to ensure your site has a ‘professional’ look.