Before you set out to develop your mad overclocking skillz, ask yourself what it is you're trying to achieve. Do you intend to make an older PC fast enough to keep up with the Oblivion-playing-Joneses, or are you a performance junkie?
If even a small portion of your zeal falls into the former category, then this memory isn't for you. Unless you have a very new motherboard, the chances are you won't be able to run this at its stock speed - a full gigahertz, yielding a bandwidth of 8GB/s. Even if you can, sticking to quality 800MHz stuff will offer near-comparable performance and cost you about £100 less.
If you do want the best, the performance gains from using high RAM speeds, even on a Core 2 Duo Extreme Edition, are negligible at stock speeds. This isn't the best RAM for reducing latencies beyond the specified 4-4-4 either - it was painfully unstable at 3-3-3 at 800MHz.
If you're the kind of PC user who wants to take an Extreme Edition and push it to the max, Titanium Alpha comes into its own. It's fast out of the box, and guaranteed for overclocking - specifically for up to 2.4V. If you're overclocking to ludicrous levels, this is the kind of RAM you'll need to keep it fed. Otherwise, you're paying £100 for a fancy heatsink.