Zalman heat sinks, quality products really, you want then to feel assured that they are not geting riped off. This can be done with something as simple as good photographs. My dad is an internet marketing salesman, basicly sells webpages to people among other online services, him being the owner of the company and lead salesman has tought me a lot about customer relations and security.
The chief thing to remember is people are spending money they earned, so show them they are geting their moneys worth and security and you have a good customer and a most likly returning customer. Just my two cents, I may have gotten a bit off topic here, sorry.
-Ryan