I personally would recommend a cheaper (smaller) TV and to spend more on the speakers.
You can get a great receiver and sub for a $1k each, but I honestly think that the speakers should be the biggest investment. But I'm much more of a sound guy than a speaker guy.
EDIT: Sorry, I forgot to actually answer the question(s)
Yes, I think it is great fun to spend other peoples money, especially in the amounts you're talking about, you can put together your dream system (or part of it depending on how lofty your dreams are), you still get to enjoy the system when you go hang out there. And I love seeing the look on peoples faces after you've got everything set up and dialed in, The WOW expression is priceless.
I don't like wireless speakers, or wireless anything for that matter. I work in the wireless sensor networking world, and I have to deal with so many problems at work, I feel very uneasy about wireless for the most part.
I would much rather run cables everywhere