Jessica Enders has an interesting article at A List Apart on Zebra Striping: Does it Really Help?
Her main points considered are does it increase accuracy, or speed. The raw statistics don't show anything statistically significant. The readers did report a 46% preference for zebra striping, but 36% said they didn't care.
I believe that anything that improves the readability, or visual appeal of information is going to be helpful to users. I also believe that with wider screens and more space between columns, the striping is more helpful.
An example of zebra striping:
<table class="tableGrid" cellspacing="0"> <tr> <th>Feature</th> <th>Importance</th> <th>D40x</th> <th>D80</th> <th>D200</th> </tr> <tr class="gridItem"> <td><strong>Viewfinder</strong></td> <td style="text-align: center">1</td> <td>.8x</td> <td>.95x</td> <td>.94x</td> </tr> <tr class="gridItemAlt"> <td><strong>Aperture Dial</strong></td> <td style="text-align: center">1</td> <td>No*</td> <td>Yes</td> <td>Yes</td> </tr> </table>