cables
I spent a small fortune on cables. Everything I have read since then makes me feel stupid and that I paid too much, and I got a deal. Gene, the head of this site really likes impacyt acoustics sonic wave speaker cables. I'm considering ordering a set with spades to bi-amp my front and center speakers and running them to my top binding posts. I have Audioquest Rockefeller cables now and while they sound good, and I got a good deal off retail, probably overpaid.
For interconnects, HDMI, Digital Coax and Opticals, look at Bluejeanscables.com. people here seem to love them. They also do speaker cable.
As far as having one receiver to do all your work, separates is always going to be a better solution. No receiver, other than the high high end British receivers can live up to their power ratings with all channels being driven. You are relying on one box to do your amps, processing, video switching, etc. A sepearate Amp is always your best option for clear, and controlled sound, especially for your main speakers and music.
Hope this helps.