Vault VCS - SourceGear Vault Pro is a version control and bug tracking solution for professional development teams. Vault Standard is for those who only want version control.
TortoiseSVN - The coolest interface to (Sub)version control
Microsoft Visual SourceSafe - Microsoft Visual SourceSafe (VSS) is a source control software package oriented towards small...
SnailSVN - Similar to Tortoise SVN for Windows but integrated into Finder
Mercurial SCM - Mercurial is a free, distributed source control management tool.
SmartSVN - SmartSVN is a graphical client for the Open Source version control system Subversion (SVN).