It does not matter how beautiful your site is, if you do not register it with the search engines, you are selling your site short and eliminating a lot of visitors to your site.
The professionals saying that "if you build it, they will come" does not apply on the Internet. It is more like "if they don't know about it, they won't come". But listing your site is not enough, it must be listed on top 20 for you to get visitors out of it.