VS 2010 code analysis reports the following:
Warning 4 CA2000 : Microsoft.Reliability : In method \'Mailer.SendMessage()\', object \'client\' is not disposed along
using (SmtpClient client = new SmtpClient()) { client.Send(Message); DisposeAttachments(); }
Interesting - contrary to .NET 3.5, SmtpClient implements IDisposable in .NET 4.0, learning new things every day.