Personally, from an architect's point of view that Titanic one is just stunning. If I ever move out of this condo that is the first thing I will build even though I think $70,000 is the MINIMUM you should spend on one of these rooms.
Anand over at Anadtech is in the process of installing a home theater that is just nuts.
Here is the latest one of his blog posts about it:
AnandTech
Go through their Blog section and find the other Theaterblogs:
AnandTech