Subversion

• It is good.

• Versioned directory.
• Versioned rename.
• Atomic commits.
• Cheap branching and tagging.
• Offline diff.
• Active community.
• you love it and it loves you back.

subversion/libsvn_fs_base/notes/fs-history:
                   Subversion Filesystem History
        (a love song for libsvn_fs, by C. Michael Pilato)

"Disks are cheap, bandwidth is expensive"

No, we don't need to wait until 2012 to see its problems and have the next-generation.