You have quite a few nice suggestions in this thread so far. I would suggest, you compile all and plan, plan, plan. With that budget, you can create a very nice room as regards to Video and audio, if carefully planned.
Projector - I would suggest looking at Epson 8200. Lot of reviewers like it more than Panasonic, especially for black levels and contrast. One very good site to look for projector reviews is
Projector Reviews – Information on Projectors. Go there and read up on both these projectors.
Screen and Audio - These go hand in hand. You can go with acoustic transparent screen or non-acoustic. Acoustic transparent has its own benefits, like putting the speakers behind it. This will allow you to use the same left/right speaker also as center speaker, the sound comes behind the screen (vs below the screen), hides the speakers and give it the feel of cinema theater. Another benefit is that you can treat the wall behind screen acoustically and you will have the cleanest front soundstage. Sam has suggested SMX, but they are out of business. Another option for acoustic transparent screen is Seymourav. There also Stewart filmscreen, but they have holes in the screen instead of weave.
Once you have decided which kind of screen you want, then go for aspect ratio. If you want 2.37 aspect ratio, then plan on putting anamorphic lens + mount + scaler. I had an anamorphic lens but I got rid of it. Instead, I went for taller 16:9 screen. No more extra piece of thick glass between projector and screen. But your choice, decide on the screen size and then decide on what kind of speaker you want.
About audio - the biggest difference maker will be the room itself. It's all about placement, you may buy top of the line speakers, but if those are not placed properly, you will not be doing justice. If want to put speakers behind screen/close to walls, then better go for speakers with no ports or ports on front. AT screen will allow better placement for speakers widthwise. You should put the speakers at 1/6 times width of room from left/right wall. Non AT screen and you will have to first find the placement of speakers and then decide how much room is left for the screen.
The side speakers should be on the side of listening position. This is irrespective of 5.1/7.1. If you are doing 7.1, then two speakers need to go in the back. Also, see if you can hold off your receiver buying for couple months away - there will be new receivers announced soon.
And the most important thing - subwoofers. Whatever your budget for subs is - divide that and buy multiple subs. I would buy multiple subs than buying a single powerful sub. Buy 4 subs and put those one in each corner. You can even go for DIY option here and get 4 subs built. This will give you smoother, consistent bass compared to commercial offerings of just one or two subs. After this, you can then start planning about acoustic treatments and absorbers.
One last advice. Think of everything as one system, rather than breaking it up like components. Plan everything, think how everything will come together. Once you have good idea, then start buying. Good luck in your adventure.