25,000 for the home theater

With your budget I would figure the cost of a good acoustical engineer into it.

If you want the 'big' picture, you will have to get killer deals to still have the 'big' sound. Is your priority screen size or audio? You can get a great sounding audio setup w/Revel speakers, a B & K processor/pre and a number of good amps - EAD 2000 comes to mind, Outlaw if you are looking to save $ and still have some juice, and a good buy on some Sunfire or Velodynes for subs, if you run short.
BTW, please do not settle for just one sub, especially passive, trust me on this, I have five powered subs and my amps never overheat. And when there is LFE in a movie, you feel it. I would definitely get some good used connects, and
buy the speaker cable new so you can get the lengths right,
unless you measure out carefully and can find a used match.
I have had good luck with Tributary silver or silver/copper
at $5.50/ft or $ 4.00/ft respectively. There is better of course, but at least stick to something a step up from Kimber PBJ's and 4TC in your system price range. Maybe Nordost/Harmonic Tech Pro 11 or Straightwire Platinum.
Good luck!

On video, look at Fajoudia for a projector, some line quadruplers, tensioned screen and...oops. there went your
$ 25 K just on video. Maybe an 80" Pioneer Elite Pro RPT will keep you on track, unless you can scarf up some great used/demo deals.
You can have great sound, a solid front projection system,
and new components - but not all three. Not for $ 25K. My
vote is get the largest RPTV and put the rest into first class audio. Unless you find a deal or three.
If you must have the big screen, an alternative speaker setup is JMLabs( I saw one lately used for $ 3,100) w/a couple of subs(three is ideal, two 10' or 11' Sunfires in the corner and a Velodyne 15" main sub will run fast, clean tight and deep. And leave your front end to produce effortless mids and highs. I personally like extra speakers on the front/rear/sides. I am still working on the sides and extra rears, but even the front effects help out with the ambience on good DTS/DD DVD's or CD's. A progressive scan DVD is a must, Toshiba is good for the $ or you can look at
some $ 1,500 models for not much difference in picture/sound quality over the internet priced $ 600-$1,000 units.
Genesis makes great HT speakers, natch, but a little pricey
even with this budget. Of course, if you can pick up a deal,
I would grab it.

Definately get one of those Pioneer big screens. I don't know the model, but once you see it, you'll know. I like B&W speakers for HT...great vocals.

If you haven't bought your system yet - check out James Loudspeakers - I heard an HT setup with them recently in Scottsdale, powered by Tag McClaren amp & processor(expensive but scary good on Gladiator, and awesomely musical on a CD of Dire Straits).

If this system is for both home theater and music, be sure to check out the Pre-amp processors that have a good analog section, such as the Bryston SP-1. Also, check out the new Bryston 6B-ST 3-channel amp. A few if these powerhouses could probably tame any home theater speaker setup.