TortoiseSVN - The coolest interface to (Sub)version control
SVN Notifier - SVN Notifier monitors your Subversion project repositories for changes.
SnailSVN - Similar to Tortoise SVN for Windows but integrated into Finder
Slik SVN - SlikSVN is a free subversion client for the command line.
Xversion - Super easy enterprise class version control.
Assembla - Integrated, on-demand tools to build software faster, with less stress. Get started for free and find out why over 800,000 users trust Assembla.