As an additional answer (or to compound on the existing answers) you could write an extension method to accomplish this for you within the DirectoryInfo class. Here is a sample that I wrote fairly quickly that could be embellished to provide directory names or other criteria for modification, etc:

Edit: I also think this method could probably be simplified or awesome-ified if it used LINQ to achieve the construction of the array, but I don't have the experience in LINQ to do it quickly enough for a sample of this kind.

Edit 2 (almost 4 years later): Here is the LINQ-ified method I would use: