Here is a collection of well designed sites that make use of CSS.
How do you pick the sites?
Well first they have to be done in CSS. Tables can only be used for tabular data. Second they just have to look good to me. Beauty is in the eye of the beholder so I do not expect every site that is posted to be liked by everyone or even anyone. Also do not expect a site to be posted just because you sent it in.
With the large amount of submissions I get daily and the increasing number of showcase sites, getting your site into the Vault will now be more challenging. I look for use of color, typography, whitespace, IA and how they all fit overall in the site's structure.