What is the most flexible serialization for .NET objects, yet simple to implement?

[XmlArray("Foo")]
[XmlArrayItem("Bar")]
public List<BarClass> FooBars
{ get; set; }

<Foo>
    <Bar />
    <Bar />
</Foo>

using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;

public class Serializer
{
   public Serializer()
   {
   }

   public void SerializeObject(string filename,
                  ObjectToSerialize objectToSerialize)
   {
      Stream stream = File.Open(filename, FileMode.Create);
      BinaryFormatter bFormatter = new BinaryFormatter();
      bFormatter.Serialize(stream, objectToSerialize);
      stream.Close();
   }

   public ObjectToSerialize DeSerializeObject(string filename)
   {
      ObjectToSerialize objectToSerialize;
      Stream stream = File.Open(filename, FileMode.Open);
      BinaryFormatter bFormatter = new BinaryFormatter();
      objectToSerialize =
         (ObjectToSerialize)bFormatter.Deserialize(stream);
      stream.Close();
      return objectToSerialize;
   }
}