Just to touch on #4:
If you really eventually want to run that many speakers, and you're going to get a $1k reciever now, make sure you get one with pre-outs. That way you will have access to the unamplified signal for each channel which you can then pass to a seperate amplifier. A reciever is essentially a pre-amp/processor (pre/pro), an amplifier, and a radio tuner all built into one box. The pre/pro section allows you to do input switching and decoding/dsp, the amp just amplifies the signal, and the tuner obviously lets you listen to the radio. So, if you get a reciever that has pre-outs, basically that lets you continue using the pre-pro and radio tuner, but just skip the amp section. You'll end up needing a lot of amps to power all those speakers, and you have to pass the amps an un-amplified signal. You could get a nice set up now, and then as you fancied down the road you could pick up some more amps and speakers to expand.
