(picture borrowed from Ximbot)
I don't thrive on conflict....especially when wrangling a merge involving hundreds of files and many hundreds of merge conflicts.....but...when I find myself dealing with such a situation, I love....love....love using Emacs/Ediff and most especially M-x vc-resolve-conflicts.
The only other "tools" I recommend for wrangling a large merge are a good night's sleep and lots of coffee.
