I have a viewing room in my house with a ten foot screen. It is a projector system and really not that expensive. I put the entire thing together for about $1000. It is far from state of the art but it works for us.

You don't need to spend a lot of cash. Pick up used stuff off of Ebay and cobble a system together. It all looks and sounds great and when you start getting into the very, very high end stuff it is just like high end cars... Eventually you reach a point of diminishing returns.