Comparing files and alternatives(?) to Diff

Continuing the ‘what tool’ theme from last week, today’s topic is ‘Diff’.  

I frequently install windows versions of various Unix command line utilities via the Gnu Utilities for Win32 project.  Diff is particularly handy not just for the programming side of automation, but also for comparing output files from automation as well as database queries.  Occasionally though, I need the niceties of a graphical tool that handles side-by-side comparison of file differences a bit more nicely.  So I installed KDiff3 (http://kdiff3.sourceforge.net/), and it seems pretty good, supporting three-way comparisons.

I also looked at Winmerge which has a portable version.  It seems to have a nicer file diff view, but KDiff has a nicer view of folder differences.  Given that it’s portable, it will go onto my tester toolkit (although there’s some evidence KDiff may be portable enough for my needs).

Are there other diff tools I should know about?