The OCZ PC2-8800 Gold modules impress with blazing 1100 MHz straight out of the box. If you are looking to get even more out of this memory, then OCZ's unique voltage warranty allows you to increase the voltages to 2.52V, without invalidating your warranty. When doing this you should make sure, to have some airflow around the memory, just to make sure it doesn't overheat.
The high voltage requirement of 2.4V might be a problem on some motherboards like the Intel D975XBX or the first revision of the ASUS P5B-E. However, even when run at only 2.0V you can still expect clocks well over DDR2-1000.
If you don't need the extremely high clocks offered by this kit, you will still profit from the huge clock headroom, because you can you can tighten the timings a lot, even down to 3-2-2-4 and still have a serious overclock from the 266 MHz baseline of your CPU. Since this memory is able to run a wide range of timings it allows you to optimize the memory settings to match your system setup. Should you ever need any assistance, OCZ offers excellent technical support for all of their memories.
Unfortunately all good things come at a price, which is $449 in this case. It is definitely a lot of money to spend on memory. So if you plan on buying this memory I suggest you make sure all your components are balanced out properly.