DDR3 has really slack timings, but high frequency. Thing is, even the fastest quad core only has a 1600mhz FSB, and 800mhz DDR2 in a dual channel motherboard is a 1:1 bandwidth match. Nothing more is needed. You'll even get tighter timings with DDR2 so probably better performance.
Of course higher speeds are nice for overclocking, but the only Intel chip with a 1600mhz FSB is an Extreme edition, with unlocked multipliers, so you dont need to up the FSB speed anyway.
DDR2 goes up to 1066 now, mebee faster I cant be bothered to check... Well in dual channel thats good enough for FSB 2132. Thats the same as setting the motherboard to 533mhz, even with a chip like the E6300 which only has a x7 multiplier your still talking 3.72Ghz. There really isnt much need for DDR3 at the moment, unless motherboards go back to single channel mode. In theory single channel mode offers latency advantages as its a simpler design, but it needs superfast ram, which generally more expensive, compared to running 2 cheaper slower sticks in dual channel.