Which memory - PC2 800 or PC2 1066?

I'm now in this position where I might have to replace my memory and want some suggestions on which one would be worth buying. I have the ASUS P5b Deluxe/WiFi AP motherboard with the 1238 bios(beta) and e6420 CPU@2.13 Ghz(non overclocked).
I do want to overclock my system in the future(which would still not make much a diff), but given the limitations of my system is it worth concidering the PC2 1066 memory, or am I better off with PC2 800, or PC2 667. I am concidering utility, performance/price, and maybe reusability(if i ever decide to upgrade in the future). So here are some of my choices with the price, so you can figure out(performance/price)-


PC2 800 CORSAIR 4GB (2 x 2GB) TWIN2X4096-6400C5 $45
PC2 800 OCZ Reaper HPC Edition 4GB (2 x 2GB) OCZ2RPR800C44GK $35
PC2 800 CORSAIR XMS2 4GB (2 x 2GB) TWIN2X4096-6400C5C $35
PC2 1066 CORSAIR DOMINATOR 4GB TWIN2X4096-8500C5D $65
PC2 1066 Kingston HyperX T1 Series 4GB (2 x 2GB) KHX8500D2T1K2/4G $60
PC2 1066 CORSAIR XMS2 4GB (2 x 2GB) TWIN2X4096-8500C5 $55
PC2 1066 OCZ Reaper HPC 4GB (2 x 2GB) OCZ2RPR10664GK $45


I'm open to other suggestions too... let me know what you think...

I got same MB and got 2 of theses kits.. with a total of 8GB and I started to get unrecoverable memoryfaults, not nice.. picked out 2 units to see if it stops if it doesnt ill change the dimms the one
on the shelf now, maybee some of em are just busted..

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I use this for 3 moths

http://www.newegg.com/Product/Prod [...] 0ballistix

are really great and comes with LED's, the only problem is that in this model only comes 2x1GB....or check in www.crucial.com, exist many models with good price and performance.

But, personaly, if you read the rewiev about memories published here some weeks ago, you can find that the difference between the PC2 800 and PC2 1066 isn't really big....if you want have some increment of performance buy DDR3.....