It depends how intrinsic the HA is to the house operation - Say if you remove some elements, will the lights fail to operate?
I personally would remove the Comfort Panel as this is still quite expensive to replace and the suppliers are few and far between (in the UK). As for CCTV, I might remove the cameras depending on how expensive they were.
Home Audio (unless Sonos), I would leave / offer for sale, as removal of ceiling speakers would create whacking great holes in the ceiling....
Something also to consider is absolving yourself of 'aftercare support' if you choose to any system - I imagine that phone calls asking me how to pair my iPhone with the Audio System would get tiresome after a while
Vangelis