Associate
I've just ordered a CoolIT as it's on offer - I decided that although I'm running an intel Q6600 (at 3.1GHz), the £15 wasn't going to make too much difference on my system. My primary concern was the air flow around my system was hampered by the ATI 5870 I recently added, and now that shouldn't be too much of an issue, as I believe that this will dump the CPU generated hot air outside my box.
Good thinking, with GPU's being as hot as they are these days you would be well served to dump as much heat out of your chassis as possible.