Update 2: After more focused tweaking, I've improved my results. Through increasing the CPU voltage by 0.0125v, I was able to get the CPU up to 3.125 GHz and the FSB to 1380 Mhz. I talked about that earlier. After assuring myself that this was a stable setup, I started working again with the RAM. I set the SDRAM voltage to 2.1v and bumped the DRAM up to 870 MHz. This arrangement tested fine under memtest86 and is now running smoothly.
This new overclocking setup seems to be a real sweet spot. The system was fast before, but now it really flies. It seems that the E6600 CPU really likes the ~3 GHz frequency range, running effortlessly faster than a stock E6800 Extreme which sells at over 3 times the price. The Intel Core 2 Duo E6600 has to be one of the most cost-effective CPUs to hit the streets in many years