I picked up this SLI mboard + q6600 combo for $300 yesterday from Compusa. So glad tigerdirect bought them out because now I get tigerdirect prices in my own home town. This deal is available online for those that may be interested in an SLI'able upgrade.

XFX nForce 680i LT SLI Motherboard CPU Bundle - OEM, Intel Core 2 Quad Q6600 Processor 2.40GHz OEM

The only downside is the combo does not include any cpu cooling. For me this was fine because I had a Thermaltake Big Typhon VX sitting around.

For memory I spent $60 (after rebate) on:

OCZ SLI-Ready Dual Channel 4096MB PC6400 DDR2 800MHz Memory (2x2048MB)

Total cost of Upgrade: $385.2(After Tax)