Matching CPU and memory

Hello,

I am ready for an upgrade of my system and decided to go for a pentium dual E6500.

When doing some reading on overclocking which I intend to do, I stumbled upon the importance, well how relative that is, of matching memory speed and cpu speed.

The e6500 has an fsb speed of 266 MHz where the memory I intended to use: ddr2 800 mhz has a 200 MHz bus speed.

Although many people use this configuration, the cpu's 266 MHz and memory's 200 MHz are not a match.
My first question is if there will be a significant difference in speed and stability of the system when I would install 1066 MHz memory with a bus speed of 266 MHz which matches the CPU's fsb speed?
This has 2 advantages: faster memory and a match with the fsb.

The second item, considering my future overclocking plans,
when raising my 266 MHz fsb speed, I will never get a good ratio using 200 MHz memory, where the 266 MHz memory version can be tuned hand in hand with the 266 fsb.

Now, is using 266 MHz memory indeed something to consider or, when in use, will 200 MHz do just fine, also with an overclocked fsb?

The reason I ask is that I already bought 800 memory and I want to know if it's really worth it to change it for the 1066 version?

And thanks for the very good article about overclocking on this website!