Change Git Default Editor in Windows

On 32 bit Win OS:

git config --global core.editor "'C:/Program Files/Notepad++/notepad++.exe' -multiInst -notabbar -nosession -noPlugin"

On 64 bit Win OS: 

git config --global core.editor "'C:/Program Files (x86)/Notepad++/notepad++.exe' -multiInst -notabbar -nosession -noPlugin"

Obviously the C:/Program Files/Notepad++/notepad++.exe part should be the path to the Notepad++ executable on your system. For example, on Windows 7 it's likely to be C:/Program Files (x86)/Notepad++/notepad++.exe .