Since you're building a house:
Room Suggestions:
0. Assume this hobby/entertainment will cost more than what you have as a budget.
1. Room shape should be rectangular
2. Aircon noise level is important, a split-type 1 hp is probably the most quiet (aim for < 30db noise level)
3. Windows are a source of outside noise, so keep this in mind when choosing type/size of windows.
4. A purely concrete room will not sound nice at all, it has to be "treated". Note how the cinema's have wooden panels in an all concrete structure. Take a look at their ceiling. Carpets, sofas can also help, etc...
5. If you have neighbors, and need to keep it noise level down, you may need to build a room within a room (unrealistic).
6. You may need to plan your in-wall wiring (speakers,video) way ahead. TV at front? Projector at rear? Speakers 5.1? 6.1? 7.1? 12.2??? Also, give the room an independent electrical circuit breaker/wiring (ie. no outlets wired here connects to the kitchen appliances in the next room) to prevent electical interference (ie. from a blender in the kitchen)
7. You may want to use electrical cord (AWG 12) like I do for speaker wires, they run inside my walls, inside PVC.
Equipment:
0. Best to demo (demo without special effects/DSP on) before buying, and bring a favorite disc.
1. Try Wharfedales for speakers, they sound really good, mine cost P18K (L-R/C/2xDFS). I'm almost sure B+W/Mission speakers may sound better, but at 3x the cost, they definitely don't sound 3x better. If on a budget, and prefer small speakers, try Yamaha (5.1), only P11K.
2. For receiver, I suggest Yamaha (P11K cheapest), HK, Marantz (P9K cheapest?), Denon, Onkyo (not the consumer types like Pioneer, Kenwood, Sony, JVC). No need for THX stuff, It's almost impossible to meet all the THX standards anyway (room design, wiring, power, equipment, etc...)
3. For DVD player, must be progressive, and try to get one with a DVI/HDMI. I suggest Pioneer. On the other hand, those cheap P2000 made-in-china DVD players play just about any DVD disc no matter how badly made/scratched they are.
4. For TV, I suggest LCD, better on the eyes (no radiation daw).
5. For Projector, I suggest Panasonic (PT-AE900 = P78K), or wait for LED Projectors (10,000-20,000 hour life)
See my dedicated HT room (7 years in the making and still on going):
http://pinoydvd.com/board/index.php?topic=55046.0