As I've said before negative space is a very underutilized aspect of graphic design. So when I see good writing on that subject, it catches my eye. This morning I spotted an article by Mark Boulton on A List Apart. Mr. Boulton's Whitespace article covers many of the different ways that whitespace is used in modern design. From Direct Mail:

I soon discovered that the graphic design principles I'd learned in college were of little use when I designed for direct mail, where big, bold, and crowded is the order of the day. In the words of one client - words I will never forget "whitespace is empty space."

To Brand Positioning:

A lot more goes into brand positioning than just whitespace, but as a brief lands on your desk for a luxury brand, it's very likely that the client - and their target audience - expects whitespace and plenty of it to align the product with its competitors.

To everything in between. Go read the whole article, it's worth your time.