Flash can add to the attractiveness of your website in a greater way. A Flash banner or animation not only attracts an onlooker but also helps in better information dissemination in the shortest possible time.
However, when designing websites with the help of Flash aspects like the nature of your business, psychology of your target audience, faster loading time and search engine compatibility need to be taken into consideration. First of all decide whether your website needs flash or not. If you are dealing with artistic products, online games etc you have to design the website with help of Flash(completely or partially).
While designing, make sure that your website can easily loaded on all major browsers. To enhance search engine compatibility of your website, you can avoid All-Flash approach. If All-Flash is required, design a no Flash version for the prospective customers who are not interested in Flash.