Your home theater space is very large, which is an advantage in many ways. There's room for whatever equipment you might need. But it's a multi-use room, so maybe you can't go too big. If it were my large room, I'd pursue some kind of good projection video system.
On a somewhat smaller scale (if you use maybe just part of your room for this rig), I've been happy with a 65" Panasonic plasma. I forget the model number but plasma's IMO still the nicest picture, although admittedly it's best in lower light situations.
Given a 10K budget, which is pretty close to the budget we had, take a look at Emotiva electronics. Their stuff is well-priced and good quality, and you get into a 5-channel amp + processor for $2000-5000 depending on how well you shop their special pricing and whether you need extra amplification for a 7.1 or 7.2 system in that big space.
For video BOOM, get into some Hsu Research subwoofers. In your space I'd get two (total cost maybe $2000).
See if you can find a way to get all the electronics into a closet somewhere in the house. All of this HT junk and cabling looks terrible in a regular living space. Budget some money for cabling to do this. Get pros to help you and do it right for maybe $2000.
Speakers: we've been happy with PSB products: two towers and a center channel. I'm a big believer in doing ceiling flush-mounts for the rear channels. Putting loudspeakers (rear channels) in the middle of a family room floor, complete with speaker cabling, is crazy. Ceiling speakers sound great and really clean up the look of your system. You can do speakers for maybe $4000
Budget 12-15K total instead of 10K, and you'll be more realistic. It's only $$$ and you'll be happier in the long run.