Warning newbie posting... relating to Gabby's comment. As a retail user of websites I have always found that the way things are presented works for me. If either Adsense/affiliate link are presented professionally and in synch with the site then I would go and have a look.
Am I the only 1 to think like this or are there others?
Using both on your website is better than not using either.
I have found that direct links in your text to affiliate sites works best. Adsense ads come in second. Banner ads from affiliate sites perform the worst.