Ideally I'd like it all contained within my Tt Armour case w 25cm fan - is it a good idea to put a big rad in the front of the pc behind the drive bay covers drawing air into the pc, or possibly reverse the air flow to back2front.
You could do that; a better solution might be to mount it on the back/outside if you can. I don't know much about installing in the TT armour, but I know people have done it. Google the case name and 'watercooling' and see if you can find pictures of what others have done...I bet you find some ideas.
Don't reverse airflow...that will mess up the mojo.
Or can anyone vouch for the Prolimatech Megahelem - got a hot lga775 chip; wasted my money on a AC Freezer Extreme
I have the Prolimatech Megahelem for a core i7 920. It is a great cooler. I put a Noctua 120mm fan on it and it runs great. i have the core i7 running at 3.6 and under full load it stays well below dangerous temps.