String ****** `What's the difference between string and System.String?`_ *C# defines a number of aliases for CLR types. They may be used interchangably, and even mixed together, e.g:* :: string x = new System.String(' ', 5);. `What is the difference between using "String" and "string"`_ ("Object" vs "object" etc.)? *both are exactly equivalent, so pick the one you like best and stick with it*. StringBuilder ============= :: System.Text.StringBuilder sb = new System.Text.StringBuilder(); sb.Append(" "); sb.Append(s); writer.WriteLine(sb.ToString()); .. _`What's the difference between string and System.String?`: http://blogs.msdn.com/csharpfaq/archive/2004/03/12/88418.aspx .. _`What is the difference between using "String" and "string"`: http://www.sellsbrothers.com/askthewonk/Secure/Whatisthedifferencebetwee.htm