Git - Git is a free and open source version control system designed to handle everything from small to very large projects with speed and efficiency. It is easy to learn and lightweight with lighting fast performance that outclasses competitors.
TortoiseSVN - The coolest interface to (Sub)version control
Mercurial SCM - Mercurial is a free, distributed source control management tool.
Xversion - Super easy enterprise class version control.
Atlassian Bitbucket Server - Atlassian Bitbucket Server is a scalable collaborative Git solution.
WebSVN - Online subversion repository browser