[edit] heh, hit send too soon...
I'm running my Abit 4200 memory @ 600mhz (default is 500) with no extra cooling. It may help that my front intake fan blows towards the ram, but either way I don't have a need to OC much more than that. The CPU is running at 300 (is that 50mhz higher than normal?), so the whole card is warm, but not too hot. As for overclocking not making a difference, it definitely doesn't do as much as OC'ing your CPU. My 3dmarks went from 7200 to 7600 from overclocking my GF4, and then from 7600 to 8800 overclocking my CPU.
But back to the subject, the Thermaltake set looks like a really nice package 🙂