As a result of a bug in the modern theme (1.4.X) you may find that the number of columns being shown in your Quick Search and Advanced Search do not match with the layout specified in your Grid settings. Regardless of what your grid layout specifies you will get 3 columns. The modern theme is layout with the expectation of 4 columns and the results look poor to visitors.
Version 1.4x has brought many great features to Magento and the new way of handling themes is greatly welcomed and will encourage users to create their own iteration of the demo themes rather than editing the core code. However, a few bugs have slipped through..