Where to mount control units

So where do you mount stuff?

Stupid question I know, but I'm planning new construction and want to spec where wiring will terminate
This house won't have a basement, so I have to figure out where stuff goes.

Eventually I will end up with an HAI Omnipro and probably a russound for house audio.

Garage might be have extreme temps, so I guess an interior closet makes sense. Does it need extra ventilation? The russound amp/distribution, where to mount it? I'll need keypad wires and speaker wires to terminate at it. Do y'all mount this by AV equipment? We will have a dedicated home theatre, so mYbe it should be with that.

Feedback welcomed.

I'd put the audio in a rack under the stairs on casters. Security, I'd aim for a central closet with enough working room.
 
If the amp is hot all the time, then you'd need to consider some cooling, being a duct/return or passive.
 
The more sexy way is to get the hardware away from the theater. No need to have it all reside there if you plan accordingly.

Do you have a crawl space that is usable?  I got lucky with my recent remodel and found a centrally located crawl space with fair headroom for the structured wiring can, whole house amps and alarm system.  
 
I've decided to place the AV equipment close to the viewing area for this house.  I found myself going into the equipment room so much to change the DVD, or start up a new game with the last configuration.
 
Be glad you get to decide this now, I'm still struggling on retrofitting a house that had very little wiring when built 40 years ago.

Heat is the enemy of electronic components.  As is moisture.  While I don't know that you'd have to plan for a separate zone to condition the air for the rack, you'd do well to make sure a fair bit of an adjacent room's air can circulate through it.  There are a number of ways to accomplish this, starting perhaps with louvers on the door or wall at both high and low positions.  This to allow for convection to come into play.  That and if that's not enough then you'll have a place where you could install a thermostatically controlled fan to push the hot air out the top.