Source code - a DVCS, like Mercurial
Source art - A distributed, versioning (copy on write) filesystem. Lustre and ZFS (combined). I also hear nice things about using a VCS plus a dependency tracking system to sync only what's needed for a given task (see Shotgun and Tactic)...
Build art/code - continuous build machines publishing tested builds to a distribution system (i.e. bittorrent)