Dietary cholesterol absolutely has an impact on your body's cholesterol levels. This is the only way that the drug Zetia helps lower your cholesterol (by blocking intestinal absorption). The statins (Lipitor, Crestor, Zocor, etc), work by blocking cholestrol production in the liver. The more research that is done on the issue, it seems the more that is controlled by genetics. Just based on my research, right now I'd say that about 65-70% of your total cholesterol comes from your genetics (liver), and 30-35% is based on what you actually intake.
Hope that helps.