Jeff, I'd like to make a suggestion:
Chop a 3" or 4" wide channel in the floor, from about 2' to 3' in front of the approximate seating location to where the space behind where the stack will go. Bury a couple of 1/2" PVC conduits in the trench, with a PVC box on the room end of each, flush with the finished floor, and a 90º on the other end of each.
These ends will be in the stack area. The power conduit should run directly into the bottom of a junction or receptacle box behind the equipment, possibly directly inside a wall, and the other coax can just stub up near a wall for connection to the appropriate input jack(s) on the rteceiver or whatever switches your video.
If you want something fancier, look at
this or even
this . See more
here . Another place to look is
here . Then, patch the concrete with typical Quicrete mix.
After patching the concrete, run some 12-2 or 14-2 in one conduit for a power receptacle, and some coax and/or S-video in the other. Then, use a suitable floor plate, either the ones above, or more like the typical 1-hole and 2-hole brass plates with screw-in or flip-up covers. You can get the necessary video jacks at HD. I like the Leviton Quik-ports. The snap into frames that fit standard receptacle plates or Decora-style openings.
Then, buy or build a suitable coffee table with drawers, a lower shelf, or some other type of compartment that could double as a gaming console. Now, you can plug the X-box (and whatever else) in for game-playing, and hide them away for safe keeping during movie-time.
How's that for a dual-purpose room that doesn't have to look like it? Plus, if you ever get a front projector, and decide you'd like it on the floor, and/or built in to another table, you already have the power and video feeds in place. If you like, use a 3/4" or 1" conduit for the video run, for RGB-HV, component, or other multi-cable video needs.