There's basic underlying usability rules that permeate through everything.
The human eye scans like an F.
It's almost the golden rule of design. Always build your layouts in an F structure for the most important items.
A list design goes hand in hand with complimenting the F average.
A prime example is yahoo.com VS yahoo.co.jp
White space is an important tool in controlling that density.
I too guessed and have always believed vertical listings are "more natural" way of consuming information than the grid listings. Grids are too overwhelming to digest any of the information and make a decision. They are probably good to browse sometimes.
I also wanted to say that a common perception that prettier is better is rarely true. Google is a great example and so was Plentyoffish. Utility and usability pretty much make the biggest difference and can make up for lack of pretty design. Infact sometimes pretty design is often not the most usable design.