Onkyo 606 for my home

[Kitsune]

So I want to buy Onkyo 606 and I have a couple of questions (I play Blu-ray on my PS3 and I'm totally green when it comes to HD sound and receivers).

1a. If I pass the signal through the receiver and into the LCD (Sharp 52XL1E - 1080p compatible ) will there be any loss in picture quality (will it still be 1080p) ?
1b. Can I hook up my XBOX 360 the same way ?
2. Perhaps this questions was asked already (it probably was) but do I need to have special columns or cables to play the audio from the receiver ? Or will my five years old columns and cables suffice ?
3. I read in some thread that Onkyo 606 heats up very fast. Does this mean that I cannot use it for to long ?