Keeping code structure with string literal that uses whitespace

I would abstract it to a separate static class or resource completely:

public static class MyStringResources
{
    public static readonly string StringLiteral = 
@"This {0} a really long string literal
I don't want {1} to have {2} at 
the beginning of each line, so I have
to break the indentation  of my program";

}

With usage like:

stringLiteral = String.Format(MyStringResources.StringLiteral, var1, var2, var3);

Even better, this way you can have a nice function that requires the number of expected variables:

public static class MyStringLiteralBuilder
{
    private static readonly string StringLiteral = 
@"This {0} a really long string literal
I don't want {1} to have {2} at 
the beginning of each line, so I have
to break the indentation  of my program";

    public static string Build(object var1, object var2, object var3)
    {
        return String.Format(MyStringResources.StringLiteral, var1, var2, var3);
    }
}

Then you can’t miss variables accidentally (and possibly even strongly type them to numbers, booleans, etc.)

stringLiteral = MyStringLiteralBuilder.Build(var1, var2, var3);
stringLiteral = MyStringLiteralBuilder.Build(var1, var2); //compiler error!

Of course at this point, you can do pretty much whatever you want with these builders. Make a new builder for each special big “stringLiteral” you have in your program. Maybe instead of having them static they can be instances that you can get/set the key properties, then you can give them nice names too:

public class InfoCardSummary
{
    public string Name { get; set; }
    public double Age { get; set; }
    public string Occupation { get; set; }

    private static readonly string FormattingString = 
@"This person named {0} is a pretty
sweet programmer. Even though they're only
{1}, Acme company is thinking of hiring
them as a {2}.";

    public string Output()
    {
        return String.Format(FormattingString, Name, Age, Occupation);
    }
}

var info = new InfoCardSummary { Name = "Kevin DiTraglia", Age = 900, Occupation = "Professional Kite Flier" };
output = info.Output();