There are a lot of WordPress template and widgets that will let you combine Amazon and wordpress. Depending on the domain name you may one to go 70/20 or 70/30 with one or the other and scale back depending on conversion. I know some people do not like to mix the two, but with a little thought it mixing my give you more options. Also there are other advantages to the wordpress site, like ClickBank integration, Commission Junction, even EBay. Again it depend a lot on the niche/domain name..hope this helps.
KG