GITK - The GITK - Generalized Interface Tool Kit is a set of libraries, which form a (user) interface...
TortoiseSVN - The coolest interface to (Sub)version control
Sublime Merge - Fast git client with integrated merge tool from the makers of Sublime Text
VisualSVN - VisualSVN - Subversion plugin for Visual Studio
OctoDroid - Mobile GitHub client for Android.
Xversion - Super easy enterprise class version control.