Is this the best memory for the P5Q-E? considering the cost also?

CORSAIR XMS2 DHX 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel

$109.00 with $30.00 MIR for 2x2gb

Using the Intel Core 2 Quad Q6600 Kentsfield 2.4GHz LGA 775 Quad-Core Processor Model

Crucial memory is more stable than Corsair on all Asus mobo's.(imho)

This is true IF you can get some that is good. The new single sided ram is not the same and they have lost my vote, just don't really know hat the recommend, but the Corsair should be fine.

Honestly, I prefer Crucial Ballistix. They are regular size with heat spreaders.

I've been hearing a lot of people running this stuff with no problem. What do you experts think?

http://www.newegg.com/Product/Prod [...] 6820231166

http://www.newegg.com/Product/Prod [...] 6820145197

you cant go wrong with those

The RAM you posted are fine, running those myself on the same board.
Just be sure to get the ones with 4-4-4-12 timings.
You will have to manually set the timings and 2.1V ram voltage in the bios as the board set them to 5-5-5-18 by default.

Hope this helps.

anyone met memory compatible problem?