[piscisaureus]

I find "beyond compare" to be a very good merge tool. It's not free, but not very expensive either, and works well with git.

(I'm not affiliated with them in any way)

[badminton1]

Beyond Compare is a good tool. It allows to compare full directories, ignore whitespace, etc.

I recommend Perforce's as a merge tool because it is better than average at the specific task of merging.