Don'te waste $ on expensive wires. You'll never be able to tell the difference. Maybe you could measure it with electrical equipment, but it won't make a huge difference at all.
Monster cable is a HUGE ripoff.
And *NEVER* spend extra money on anything digital. Digital is digital -- either it works, or it doesn't.
What everyone's saying is basically right. There are too many downsides to wireless speakers. For one thing, you still have to plug them in.
Do you own your place? Do you have any closet/attic space that you can use to mount amps in? If you're not averse to spending a little $, I put in a system a few years back that kicked ass -- the whole system was for about 3 rooms. Including the source equipment, I think it was about $20,000. Of course, you probably wouldn't need a $5000 turntable like this lady did
But check out Linn and their in-wall control systems. Very cool. If you get these things professionally installed, they can do a very clean job.