I'm in the process of writing a lengthy guide on overclocking. It will be followed by some benchmarks showing how CPU and RAM affects speeds. I will also have another post on PCIe overclocking and how that can affect GPU performance. And finally I will have a post on GPU overclocking and some results on that.
Another thing I plan to post is a review of scaling on my 5850s in crossfire. I've done this before but I want to update it with some more current benchmarks. I might also try to incorporate this into the PCIe review but we'll see about that.
Anyway, these are in no particular order except for the OC guide, which is probably 50% done.