Answers

Surround sound is generally installed in front of and around an entertainment system including your TV or video monitor and often several locations throughout the house may need surround sound as in Home Theaters.  It should just be a few hundred dollars per system, per location to prewire surround.  If you are looking for whole house sound systems, that is a different story and generally each room is not surround but has stereo speakers and depending on the number of rooms and your distribution system, it can vary quite a bit.  Most good security systems today are wireless and I would highly recommend any glass door or window area easily accessible from the outside have glass breakage sensors.

It really would depend on the size of the system, but to rough in surround sound shouldn't be more than around $1500. In regards to security systems, most of them are wireless these days and don't have to be pre-wired into the house. I hope that helps give you an idea of what you're looking at.