I’ve been in the process of manually merging two directories in a subversion repo. The second started out as a “development” copy of the first (without branching, unfortunately). Since there’s quite a few files, I decided that a graphical diff program is a must. I usually use kdiff3, but my requirements for this are a bit more stringent than usual: it has to handle recursive diffs on two directories, and it has to be able to ignore SVN keywords (or an arbitrary regex) since all of the files have keyword substitution on LastChangedRevision and HeadURL. Kdiff3 supports preprocessor commands which can include filtering the text through sed before performing the diff (so I modified their regex to ignore version control keywords), but for some reason (perhaps either bimary differences, or metadata differences) I couldn’t get the file difference indicator in the diretory tree view to reflect this; even when ignoring keyword lines and whitespace, it still showed every pair of files as different.
Enter Meld, a graphical diff project. I’ve only used it for half an hour or so, but it seems wonderful. It’s easy to use, has a pleasing interface similar to Kompare, and even has simple check boxes in the options menu to ignore whitespace and SVN keywords - and they work! So far, I’m about half way through my 300+ file tree, and the merge is going wonderfully.