Making PC Quieter - PC Fans

Hey

I'm looking to make my PC quieter, main problem is the fans and vibration. CPU cooler is arctic coler 7 pro which is pretty quiet, and ati hd4850 stock cooler (kinda quiet unless insanely hot (which is alot)).

Case is Antec 300.

Fans are the problem so far, I have two zalman ZM3's, when turned of very silent, otherwise rather loud. The Antec Tricools at medium are pretty good tbh, no idea why they are faulted. They cause ALOT of vibration though, even with silicon washers. Here would those silicon fan bolt things work well?

Replacing my two ZM3's would be two Noctua P12's, one at the front, one at the back (exhaust), taking the place of a tri-cool fan which would be installed on the side.

All fans would have the silicon bolt things or whatever they are called.

Is this a good idea? Is there any better alternative? How can i reduce vibrations (ie if i put a can of coke on the top of my case it rattles, i can feel it with my hands), do the sound dampening materials work? if so how much do i need?

Just some questions i have, cutting it short, best way to silence my pc is ...? (continue + answer above q's if possible please)

Thanks

EDIT
Does scan stock the molex to 3 pin fan adapters?

how loud is your PSU?? Some of them can be really loud, i went through a couple on my home server till i decided to just spend the extra on something better.

Damn quiet ;) - Corsair HX520

Also for a GPU cooler, heard Accelero is great, but dont want to spend too much, how is this - http://www.scan.co.uk/Products/AKASA...e-BLUE-LED-fan , i hear it is silent and rather good?

If you are looking for silent case fans - the Noctua NF-S12B FLX is your best bet. The P12 is made for cpu coolers and radiators- the s12b pushes more air and is designed with case cooling in mind. Also, the noctuas come with anti vibration bolt things that look like this. I have them in my case and they sure seem to keep vibration low.

It also sounds like the 4850 is a big part of the problem - i haven't encountered the blue thing but the Acellero twin turbo does indeed look good and not a terrible price.