C# getting file names without extensions

When you walk a directory getting file names you get a file name with its extension: file1.txt, file2.txt, file3.txt.
How better to get file names without file extensions file1, file2, file3?

foreach (FileInfo fi in smFiles)
{
    builder.Append(Path.GetFileNameWithoutExtension(fi.Name));
    builder.Append(", ");
}

or in a linq way:

var filenames = String.Join(", ", Directory.GetFiles(@"c:\", "*.txt")
.Select(filename => Path.GetFileNameWithoutExtension(filename)).ToArray());