Intel core 2 quad 2.5 with DDR2 800/ Intel i7 2.66 with DDR3 1066

Im am looking to purchase one of the following from dell, a system with an Intel core 2 quad (2.5Ghz) processor with 6GB DDR2 (800mhz) OR a system with an Intel i7 (2.66Ghz) with 6GB DDR3 (1066mhz). However, after reading into DDR2 vs DDR3 I have no idea which is better... I dont really understand most of the technical jargon in forums regarding timings and latency. As far as I can gather, getting the i7 system with DDR 3 @ 1066mhz would give a latency timing of 2.5 nano seconds more than the Quad system with DDR2 @ 800mhz.

So, will having i7 w/DDR3 (1066) hinder the performance of the processor?
Would I even notice the latency difference?
Which should I choose?

Both are prebuilt, although different cases and motherboards, with the RAM fixed at those frequencies.

I will be using the PC for home music recording/production, and some gaming.

Irregardless of the price difference I would simply like some help in deciding which desktop to choose.

Any help would be appriciated.

and about the latencies, it all depends from the RAM itself, there are a lot of 1066 Mhz Rams with different latencies.