I do a lot of affiliate promotion and one of my biggest pet peeves is joining an affiliate program with poor affiliate graphics or none at all. I mean if you want me to promote your product give me something to work with folks!
To get around a lack of quality promotion materials or the fact that I am using an indirect affiliate service like Amazon I have started to use my own affiliate banners. They look good and they are unique to me so my visitors know I REALLY DO like these products. Here are some examples I just started using last month.