I'm building a new rig and almost for sure will be getting regular DDR2-800. DDR2-1066 is WAY more expensive then 800, and barely faster. Even speed differences from DDR2-533 and DDR2-800 are negligable, and overclocking doesn't increase performance much either. Why pay tons extra for faster RAM when it would be more worth it to buy a better graphics card?

faster RAM allows for a higher FSB speed without having to overclock your RAM too. DDR2-800 is good up to 400 MHz FSB for a nice 1:1 ratio but to go over 400, not only do you need to push your CPU harder, but also your RAM, which pretty much always involves pushing your northbridge harder too

Fewer components running faster than stock = lower power consumption, lower heat production, and lower chance of something breaking

Another thing to keep in mind is you'll be able to get tighter memory timings by underclocking higher-speed ram, for example underclocking DDR2-1066 to DDR2-800 would make it easier to get 4-4-4-12, or possibly even 3-3-3-10 (but that one would require some serious tweaking to pull off and be stable)

Edit: Also I'm not sure about the prices in the store you're sourcing from but I recently bought 8GB DDR2-1000 for about €10 more than I'd have paid for 8GB DDR2-800. Since my FSB runs at 400MHz, the extra headroom is nice for tighter timings

To compensate for a small c***

The thing is, DDR2-800 is solid and will OC as high as you need it to in most situations. Maybe if you are a set it and forget it kind of person or if you are scared to push the 800 you want the 1066. I bet some people don't even know how to clock it properly and leave it down clocked at 1:1 with their 333 FSB anyway.

1:1 shows the best performance in most cases from what I've read around the internet. Going to be experimenting a bit with it tomorrow, check out my thread "Which ram:fsb ratio will see best performance" for updates

It really depends on your goals. Not everyone buys memory based on $$$ per gb. If you want to OC a CPU really high and also get maximum memory bandwidth, it is good to buy the fastest memory you can afford. It's like high performance car parts.

Word. I love to see people do their own tests. Put your fire retardant suit on though.

I will 99% agree with that. I see it more like bottle neck prevention rather than seeking performance gaining. But yeah, it definitely depends on what you are using it for too.

There are a select few who don't have spending caps and value the warm fuzzy feeling of having the #1 fastest product over having better performance / $. (I am jealous of you BTW) Then there are those who have a legit reason for the upgrade but I think the majority of people don't know where to put their money to get the best performance / $.

If you had a $1000 limit and want to build the best gaming machine possible, would you get DDR3 RAM? HECK no, but some will do it anyway. It is like buying a Ferrari if you only drive to the grocery store a mile down the road. = <- that much overboard.

I wasn't able to find a definitive answer to what I was looking for so I figured that since I know what I'm doing, I'd aid the community by providing an answer

I haven't tried it but as far as I have read, bumping up to something like 5:4 doesn't do much. But, if it doesn't hurt...then why not?

Just get 2x2GB DDR2 with 4-4-4-12 timings and you to just fine.
4GB Dual Kit DDR2-800 F2-6400CL4D-4GBPK 4-4-4-12
http://www.gskill.com/en/f2-6400cl4d-4gbpk.html

AFAICT, essentially all RAM sold as faster than DDR2-800 is just factory-sanctioned overclock RAM anyway, so whichever way you get to those higher speeds, you're overclocking the RAM. The extra dollars for the higher-speed RAM gets you a manufacturer's guarantee that it will overclock to a certain point.