ASUS Rampage Formula Intel X48 ATX Motherboard for $288.99
Newegg offers the ASUS Rampage Formula Socket 775 ATX motherboard for $288.99. The ASUS Rampage Formula is based on the Intel X48 chipset, and supports LGA 775 processors including the Core 2 Quad, and provides 1066 FSB. It has four memory slots for up to 8GB of DDR2 memory, two PCI Express x16, three PCI Express x1, and two PCI Slots.

NewEgg offers the ASUS P5Q-EM Micro ATX Intel motherboard for $134.99, after $5.00 instant off. The ASUS P5Q-EM, based on Intel G45 LGA 775 chipset, has Intel GMA X4500HD graphics, and supports Quad-core, Core 2 Extreme, Core 2 Du, Pentium processor and up to 16GB DDR2 1066(O.C)/800 memory.
NewEgg offers the ASUS M3A78-T ATX AMD motherboard for $144.99. It ships for free. The ASUS M3A78-T, based on AMD 790GX chipset, supports AM2+/AM2 processors and up to 8GB of DDR2 1066MHz memory.
NewEgg offers the ECS A780GM-A ATX AMD motherboard for $69.99, after $10 mail-in rebate. The offer expires on 11/01/2008. The ECS A780GM-A HDMI ATX AMD motherboard, based on the AMD 780G chipset, supports AM2+/AM2 processors and up to 32GB DDR2 memory.
Newegg offers the ASUS M3A32-MVP Deluxe/WiFi AMD motherboard for $199.99, after $20.00 instant off. The ASUS M3A32-MVP Deluxe/WiFi based on AMD 790FX chipset, supports socket AM2+/AM2 Phenom FX, Phenom, Athlon 64 FX, Athlon 64 X2 processors and provides 2600MHz FSB. It has four memory slots for up to 8GB DDR2 memory, four PCI Express 2.0×16, and two PCI slots.