A/V zones
Darth,
Did you run cat5 or Coax for the video? I have heard of a couple proprietary systems that run video over ethernet but 3 coax for composite video is much more common.
Your audio wiring sounds fine and your options will vary based on your budget. A simple system might include a Behringer A500 amp ($180) and impedance matching volume controls in each room ($30 each). However, all rooms would play the same source.
More complex systems from Russound, Niles, etc. will allow requre a distribution amp for 4-6 rooms and keypads that will allow you to play any source in any room. Expect to spend >$1k on the amp and >$100 on each keypad. You will probably also need to have a custom installer configure this type of system.