By beautiful, we mean asthetically pleasing. This doesn't necessarily mean high effective, but they are undoubtably great to look at!
Here are some links to galleries with examples of website's that follow a specific design ethic or style:
Magazine Style - popular for blogs and news sites, these sites include many elements and images organised into categories so the visitor sees variety.
Illustrative - sites that use beautiful illustrations (drawn elements) in a range of styles.
Collage - different and fun, collage design layers visual elements
Typography - these sites are dominated by text to great effect
Vintage and Retro - very popular in 2012
Corporate/business - very common, simple and stylish
Minimal - simple doesn't have to mean boring or stark
Web 2.0 - more of a broader concept than a style per se, web 2.0 reflects trends for interaction and softer designs that can include elements of other styles