TortoiseSVN - The coolest interface to (Sub)version control
SnailSVN - Similar to Tortoise SVN for Windows but integrated into Finder
Xversion - Super easy enterprise class version control.
RabbitVCS - RabbitVCS is a set of graphical tools written to provide simple and straightforward access to the...
Slik SVN - SlikSVN is a free subversion client for the command line.
VisualSVN - VisualSVN - Subversion plugin for Visual Studio