Ashnak has already mentioned Water cooling.
In the OP you mention cooling RAM.
I suggest you concentrate on your cooling in your case. Most of the hardware is a matter of picking what you want, but needless to say, it has to be kept cool. More importantly, it needs to be done without sucking in dirt and as importantly, quietly.
Look carefully at your layouts. On my case, air is blown in from one, filtered point. There are plenty exhaust points all around the case.
Make sure the Intake filter is easily accessible. The way my case was designed by the manufacturer, the intake was on the base and the filter accessed by pulling out from the back! That is now very different with a filter on the front, behind the access door.
Think about putting in a few cardboard fins infront of the fans to increase air turbulence. These can be easily strapped to some passing cables which are generally in every PC case.
Get a decent monitor. I found this one recently.
http://www.majorgeeks.com/files/details/siv_(system_information_viewer).html
I partially like this monitor because all the important stuff is displayed right in front, organised into groups, without the need for repeated setups.
Along the bottom are a number of tabs which allow quick access to a number of other, more detailed features which may be useful from time to time.
Best of all, its free.
