well it really not all that a difficult question :
first of all, virutally ALL commercial theathers use horn based speakers and most of them play at reference level (= 0 db).
So the first step is to get a horn based system, bic speakers will give u a desired effect for a very reasonable price. (bicamerica). A little step up in my humble opinion would be klipsch (especially their thx ultra system is really worth it's money), next step would be jtr or seos or the audiokinesis system, and from there on up u can go for the reference jbl setup, tannoy, procella or meyersound but be prepared to pay luxury car money.
best bang for the buck is the klipsch thx ultra system imho at around 6 grand.
then all u need to do is find the right amps for your system, just find out what your speakers need, and be done with it. Furthermore it's important to know that even if a speaker says it has high sensitivity, that doesn't mean it doesn't need power. especially klipsh dips low in resistance, (sometimes around 3 ohms) so they will need hundreds of watts (200-300 should do it) to perform linear at reference level.
then u need a good multichannel processors, wich is definitely not unimportant, but denon makes some good budget processors, the anthem basic models are also good. if it has built in amps (=receiver) that can be uselfull for just the surround speakers, but be prepared to spend on external amps for your fronts, center, rear and subwoofer(s),(although i recommend active subs, nothing wrong with a class d powerd subwoofer !
a good starting point in finding your speakers would be a longrunning thread found here , http://www.avsforum.com/t/1387083/list-of-reference-level-high-sensitivity-spl-speakers
u might wanna take a very good look on that list as it mentions msrp price , their actualy sensitvity and how much power they really need to reach 105 db of spl at 3 m away from your speakers. this way u know what to look for on the used market, wich is still imho the way to go.