X38 with DDR3 is definitely the way to go. Its early stage silicon has already shown us that its overclocking abilities can get up and boogie, and DDR3 has also shown that under the right conditions 2000 MHz is possible.
The days of DDR2 for the Intel platform are now numbered, P35 started the trend and the X38 continues on with full speed PCI Express x16 slots. We have yet to really determine the best board for the job as we have only seen two boards based on the Intel X38 chipset, one DDR2 and one DDR3 so we can't judge who has the fastest X38 out there. But what we can say is that DDR3 and X38 is a much more happy medium than DDR2 and X38.
The introduction of the dual x16 PCI Express slots has been a long time coming, in fact we were hoping that at least twin x8 slots would have been brought forward to the P35 to give a the Crossfire users out there something to build on, but Intel simply went their own way there. X38 replaced the aging 975X which was Intel's only true Crossfire setup board with two PCI Express x8 slots.
ASUS has done a very good job on their first X38 board, based around DDR3 rather than DDR2 like GIGABYTEs first we are happy to see just how well the board overclocks at this early stage. Its feature set is beyond what we would have expected as well. ASUS has truly done a good job at this early stage of the race, hopefully with new BIOS updates and better revision silicon in the future we will see overclocking beyond the 600 MHz FSB mark.