I do a fair share of C# programming in my job, in addition to the database component. And I love using string.Format() to easily build strings. And I'm in the midst of a conversion project where I'm going to have a static chunk of XML that I'll need to use for every record getting converted, and string.Format comes to the rescue in an not so intuitive way. I'll build a string with the replacement tokens and use that string as the pattern for the format command. So it will look something like this:

StringBuilder XmlTemplate = new StringBuilder("<root><record>");
int qID = 0;
XmlTemplate.AppendFormat("<Question Id=\"{0}\">[{1}]</Question",78,qID++);
XmlTemplate.AppendFormat("<Question Id=\"{0}\">[{1}]</Question", 42, qID++);
XmlTemplate.AppendFormat("<Question Id=\"{0}\">[{1}]</Question", 999, qID++);
XmlTemplate.AppendFormat("<Question Id=\"{0}\">[{1}]</Question", 8675349, qID++);
XmlTemplate.Append("</record></root>");
XmlTemplate = XmlTemplate.Replace('[', '{').Replace(']', '}');

// while inside loop of conversion data
string XmlToProcess = string.Format(XmlTemplate.ToString(), "first", "second", "third", "fourth");
MessageBox.Show(XmlToProcess );

The only real downside to this is that I need to use square brackets around the qID value and then replace them but it's still an efficient solution for this particular problem.