The HR-02 is another passive heatsink for the CPU. Could also add a very quiet TY-140 fan to it. This way you'd only need to bother water cooling the GPU's, which make the most noise and generate the most heat afterall.
Getting a Creative card for gaming is moot now since virtually no newer games support EAX, plus Creative products should be avoided in general. Without EAX, Creative cards are nothing special. If you want a better quality card and if they're available check these out.
http://www.htomega.com/
Screen size doesn't affect performance, only the resolution. If you have a 23" and a 100" screen, both at 1920x1080, your games would play exactly the same.