Since you have some 2tb WDC greens. How quiet are they? Is the head parking feature very slow to recover from? The last green I had was a 1TB and my 2tb black is just hot and loud for nothing in my case(because I have ssd's now).
My back 640's made no sound at all, did not even vibrate, then I got my 2TB one and boy on spinup(think it is a 4 platter job or something) does it make it self known. It also seeks rather loud(not old 40gig loud tho), but this is in a rather quiet system.
I am half tempted to pop a red into my media center(I currently have a 1tb wdc blue notebook drive in that system for storage) to see how quiet it is. I do not need speed(It has a small 128 gigabyte M4 for windows and programs), just space.
30-40 idle 50-60 for most games for most cpus, some will be lower others may be a bit hotter(My 2600K @ 4.4 running folding@home gets to about 63 peak dead idle is the high 20's low 30s. You can see my media center in the image. I am not even sure how it stays that "cool"[the video card is a bit warmer at load due to the low fan speed] being a SFF case.).
Video cards vary quite a bit. but as long as they stay under 80-90(closer to 80 for your card) most cards are fine.