Thanks guys. Those all seem like good fans, but I was hoping there would be a review of the stock 6600 quadcore fan due to it being very common, and how it can be used as a 'baseline' to see how aftermarket fans compare (so users can see whether it's worth upgrading).
You'd think review sites (including SPCR!) would be falling over themselves to cover the stock ones actually.
Unfortunately, I still have the knowledge of that Intel Stock Core 2 Duo heatsink (which looks very similar to mine), and they claim it's very good. So I don't know what to think.