Prophet of Entropy

if your dead set on colour for the look of your loop. you can use dye, take some pictures of it then drain it, flush and replace it with a stable fluid for 24/7 use. Or if you want to bust out the cash use IceDragonCooling Nano Fluid and clear tubing.

I don't like the design of that block, looks like something I was looking to put on my Pentium 3 like 12 years ago. I'd go for something more modern with a jet plate in it, they are more restrictive so you might need a better pump (tried looking it up on magicool but they don't list it, to old?).

you don't grind the processor, just flatten the integrated heat spreader, the metal plate that sits on top of the processor. you can also de-lid it if its not soldered on. but for 1-2C, unless your going for crazy high OC, it's generally not worth worrying about.

a dust filter on any intake fan is never a bad idea.

Blah physics! I said noticeably mostly because his comp isn't likely to be the only thing in his room generating heat. never did see how long he said his comp is on for or how many of what type of monitor he uses. when I switched to led backlit tv in my tv room it got noticeably cooler. also use CFL bulbs instead of incandescent, if you don't have a window put a fan on the floor in your doorway to push cooler air into your room

unless you place your radiators in another room your computer will output the same total heat. the extra amount of thermal mass in the waterloop shouldn't change the speed of your room heating up any noticeable amount.

those fittings need 3/4in OD tubing to work as intended, might work anyway, but that is because if you can get 3/8s ID tubing over 1/2 fittings will stress the tubing. I would use different tubing or different fittings so I wouldn't have to worry about my tubing splitting at the fittings. since your pump comes with 1/2in barbs I would just switch tubing. don't think there is anything wrong with swiftech rads, but the XP series have a fairly high fin density ( up to 20fins per inch) which will probably restrict air flow from your fans. So either use fans on both sides of the rads for push/pull or faster/higher volume fans. Also your case supports a 4 120mm or a 3 140mm fan rad at the top, so might be worth looking at.

Like Ghost said a video card can get very heavy when water cooled, specially with a full cover block. I wouldn't want to transport one without a restraining bracket.