Compare files and directories. View changes in color, not in separate columns. Not showing data that is equal anyway improves your overview of the differences. (Works great with TortoiseSVN.) Handles XML with little whitespace by pre-parsing nodes.
Version 188.8.131.522 adds: Mini-diff in adjacent lines with difference (only from left, right for now)
NULL characters are replaced with space; XML option: treat CDATA as text; XML option: detect namespaces, nodes with the same namespace URI may use different prefixes.