I don't think that is entirely true. While people don't care if sites are beautiful before spending money with them I think they do want something that looks decent and well organized and professional. It is all about building a site that is Simple to use with very straight forward navigation that directs the user quickly to what they want and where they want to go without having to hunt for it or guess how your site works. The less clutter and distraction the better. Throw up ugly junk that you gave no thought to the layout or user friendliness of and you'll get a much lower conversion rate.
When I go to a site that is hideous or completely dorky I leave as fast as I can get my mouse to the close button. While I would never spend time doing stupid things on a commercial site like flash and slick heavy graphics, I would spend time making sure it is clean, simple and professional. I'll leave the heavy graphics to entertainment sites like heavy.com
I really never understood before why people did not care how ugly sites are. How completely ugly sites like Ebay and Amazon do so well and then never improve there sites after making so much. But then I understood it. It is all about the ease of use and FUNCTIONALITY. Most people don't care about how good and pretty it looks because the masses don't have any good tastes themselves for one thing. Two, most people are on Windows so they are already use to junky crap kid like graphics and already expect most things to look like that! Sad. And Third, most people care mostly about the utilitarian factor of getting what they want and it working they way they want it to. So if ebay and amazon were good looking with the same functionality they would still do just as well because people find what they want. It just doesn't hurt them that they are not.
So, while great looks don't matter I still think it makes a big difference to spend time planning the design and layout to make it clean and simple and professional and easy to navigate. Easy to use and understand. Think functionality and user friendliness. Don't throw up unthought out crap.