I highly recommend System.Xml.Linq.
MSDN Page for Xml.Linq
Good Xml.Linq tutorial
Keep in mind you do not have to use Linq to access your Xml data. You can use XElement and XDocument
or any other type provided as normal without Linq.
For some reason I can only put in two hyperlinks so here is a stackoverflow question that shows how to use Xml.Linq for custom types.