Improved error messages
Somebody seems to like the fact that we recently added XPaths in validation error messages. I was pretty happy to read Bob's post since I lobbied for that feature, helped design it, and tested it. Prior to this all we gave the user was along the lines of "element 'b' found when element 'a' was expected", which might be adequate for very small instances but isn't very helpful when you're staring at a 10 Mb XML document.
