[a-dub]

i've used kdiff3 for some hairy merges with good results.

back in the days when i was responsible for regular merges for a pretty big project (weekly or so, 10-30 devs on both sides, n*1e7 LoC), i took the time to learn ediff and did my merges in lucid/xemacs.

i had colleagues at the time who had nice things to say about beyondcompare.

more recently i have seen this meld thing and it has piqued my curiosity.

favorite tool for quick no-frills out-of-practice-with-real-tools visual diff is fldiff built on fltk.