The cheaper option asus P5B (not the deluxe but deluxe is better) 965p under £100 ASUS P5B i965
12 phase power at a high price for 965p chipset works with core 2 duo gigabyte 965p-dq6
all these boards overclock well and allow for up to 8GB of ddr2 ram @ 800mhz they all have raid 0,1,0+1 and JBOD. they all have dual pcie x16 slots except for the P5B (deluxe version has 2) but only the asusP5W deluxe DH works with a multi gpu solution (crossfire or sli). they all should reach sky high fsb's of around 450+/- mhz (although you'll barely reach 200mhz with an 805 due to the high multiplier), and they all work with the core 2 duo. however i think that you should, if you have the money, go for the asus P5W deluxe DH or gigabyte DQ6 as they have 8 and 12 phase power respectively. 12 phase power means when you overclock you should have very stable power management.
sorry it was a bit long and probably a bit confusing...