Polish. You can make a turd look like a professional web-site with enough polish. But even if you do that it is still a turd. People will come to your site if

Polish. You can make a turd look like a professional web-site with enough polish. But even if you do that it is still a turd. People will come to your site if it has great content even if it doesn't look "professional." Polish just makes them more likely to stay but not really more likely to return (content does that). Polish is all about getting both the "big" things right but also about getting the little tiny details right too. If you spend hours considering if your site should have rounded corners on the CSS boxes then you're doing it right...