Just a short note: KDiff3 is awesome. Its GUI is decent, but where it really shines is that you hardly need the GUI at all. I did a `svk pull`, had a conflict, decided to try KDiff3 to do the 3-way merge, and it automatically did the merge itself. All I had to do was review what it had done.
This is also the sort of situation where the advantage of using SVK over straight SVN really shows itself.