what's it cost??

All of this is completely dependent on how much you are hiring out and how much you will do it yourself. And also where you live. Labor costs can vary drastically from region to region.

That would cover a mid priced projector. You asked for the BEST 3D projector.. but did not say in what price range < $3000 or > $3000... Some people spend $20,000+ on speakers.. Bigger the room more you need to spend on speakers. and subs. Good seating can be $500-$1000 a chair.. Screen the size you mention from a quality company could be $2000-$4000 depending on lots of things.. many many many many many variables to think about, that is why it is called a hobby and takes these folks months or even years to complete a room.

So it is all relative to what you have to spend and what compromises you are willing to make. You can certainly put together a nice room for your budget,. but you have a lot of stuff to learn about as you will need to spend wisely and compromise a lot. Knowing how everything works and the advantage/disadvantage to each choice will let you make good choices and end up with a quality room with a low budget.
My advice to you is get your school debt paid off before you worry about a theater room. 0 Debt is Nirvana!

Doesn't have to cost that much, and you can start with components for your normal TV and move up to the room as budget allows. For example, the receiver, speakers, BluRay player and gaming system can all be there and working before you commit to the room. That way it doesn't have to be a budget breaker at that time.

As an example, here is a breakdown of my own theater, showing when and where the money was spent.

Equipment:
Onkyo 806 receiver - B stock, 2008 $650
Klipsch KG-4 mains - 1993 $400
Klipsch RC-45 center - Woot-off 2007 $200
Klipsch RS-? surrounds - 2007 B stock $250
Velodyne SCR-1200 Subwoofer used - $300
Panasonic BDP-220 BluRay - 2011 Shopko sale $119
Toshiba HD-DVD - 2007 WalMart Black Friday $99
XBox 360 2011 - $299
Equipment total = $2317 spread out over 20 years. Probably twice that in equipment handed down or tossed out.

I decided to create the dedicated space in August, 2010

Projector
Epson 8100 projector $1400
Elite Sable Screen 120" $320
Wall shelf mounting bracket $45
Projector total = $1765

Room treatments
Paint for walls and ceiling $85
Area rugs to cover tile floor $425
Berkline 12011 powered recliners (4) $2180
Eclipse sound and light blocking curtains (8 panels - closeout at bed bath and beyond) $120
Movie posters and frames (not counted in total because that is a different and expensive hobby)
Sound treatments $175
Room treatment total = $2985

So, my total so far is $7067, which is your budget. It helped that I had finished space available. I also did not go overboard and try to create a palace. I ended up with a space where I can turn off the lights and be absorbed in the movie. It is a space where guests can feel comfortable. By being patient, shopping closeouts, sales and some selected used, I was able to get equipment at substantial savings.

It is not finished yet. I want to add a bar at the back and some cabinets. I want to upgrade the rugs. Eventually I would like to put in a false wall and hide the speakers. I need a more formal equipment rack. All this will add to the cost, but the point is that I can do it at my leisure and still enjoy the space now.

First tip - don't waste your hard-earned money on snake oil. Buy all your cables from Monoprice.com. The only cable that should cost more than a few bucks is a long (>20') HDMI cable, where there will be a difference in quality - but it's real science (wire gauge) in that case...

Jeff

I would suggest you put the money into better 5.1 equipment and look at 7.x, 9.x and 11.x much further down the road. First, you will get much better return on investment by having fewer but cleaner sounding speakers and amps with sufficient power. Second, there is very little true 7.1 material out there. Heck, I have trouble finding stuff that does satisfactory 5.1.

Overall, put your $$ into fewer but better components. You will have more satisfaction and less churn in the long run.

P.S. also agree with Jautor (as usual)

For cables, yes, sorry. Chalk it up to life experience, unless you just bought them and can return them...

No. Unless you are seeing digital dropouts (random white speckles like "static") in video, or pops/clicks in digital audio, then the bits are all arriving just fine, and the cable is "good enough". Certainly no reason to replace any working cable - it's not going to make the picture/sound any better, but will lighten your wallet.

Even if someone could prove a $100 cable made any difference, that money would still be better spent on a better TV or speakers.

Jeff

It's all the same answer. Snake oil. Buy cables with the appropriate wire gauge for the length of the run, most everything else claimed above that simple fact of physics is snake oil.

Again, depends on the length of the run. 14 Ga electrical cord from Ace hardware is more effective and cheaper than 18 Ga speaker wire from radio Shack. The only time you need something fancier is when you are either in-wall or running parallel to power lines for significant distances.

There is a lot of smoke and mirror discussion out there that tries to fool the laws of physics. At audio frequencies, it is all about resistance of the cable. Your typical speaker shows an impedance of 4-8 ohms. You want the resistance of the cable to be an order of magnitude lower, or < 1/2 ohm for the run. That way, 90% or more of the voltage drop occurs across the speaker, and is not lost in the cable. The following calculator may be helpful: http://www.stealth316.com/2-wire-resistance.htm

You also need to guranteee that the wire can carry the current load from the amplifier to the speaker. 16 Ga wire is good for about 10A, 14 Ga for 15A and 12 Ga for 20A. All are way more than needed.

I generally use a thicker gauge than specified because it is usually cheaper for 14-16 Ga. In addition, corrosion and resistance will build up over time at the connectors, and the thicker gauge provides some margin.

Sorry if "I blinded you with science". Just the EE in me coming through and analyzing everything

About what? We've gone down a rathole about wire gauge and quality - if you've got the cables you need already, not a lot to do about it... If you need more cables - get them from Monoprice. If they're long (>20') or go in-wall, there's some additional considerations, but those are based in facts and fire code/regulations.

Back to your original topic - lots of good choices for projectors that will fit your goals - look at the Epson line for some excellent value and great images. Do you have the room you mentioned or is this just planning for the future?

Jeff