{

I wish I could say I was the clever one to think of this but I ran into it in my copy of the Python Cookbook (the original author is Xavier Defrang, the Python implementation here). It's cool enough that I ported it today - I'll know I'll use the C# implementation of it quite often:

        static string MultipleReplace(string text, Dictionary replacements) {
            return Regex.Replace(text, 
                                    "(" + String.Join("|", adict.Keys.ToArray()) + ")",
                                    delegate(Match m) { return replacements[m.Value]; }
                                    );
        }
	// somewhere else in code
            string temp = "Jonathan Smith is a developer";
            adict.Add("Jonathan", "David");
            adict.Add("Smith", "Seruyange");
            string rep = MultipleReplace(temp, adict);

}