You could easily spend 200k on the system you describe. Whether you choose Crestron, Lifeware or any other system, you have a VERRRRRRRY complex system.

Basically you are describing a system with Crestron (or some other) control system, Crestron or some other brand distributed audio system, Kaleidascape DVD server system, Crestron, Vantage or Lutron Homeworks lighting (18 zones to you might mean 18 rooms, but 18 zones in a lighting system means 18 controlled loads), a control system that can hook into a security and CCTV system, pool control and whatever else you can think of.

If you do this system as a DIY, you might be able to do it for 80-100k,if you work really hard to keep costs down, plus a million hours of your time.As QQQ mentioned, CQC can handle the control of this type of system, but you will have to supply all of the parts for your subsystems.If you are going to hire it out, I don't see how you could possibly get it done, with any of the current players equipment/software, for less than 150 - 200k.