(D0 stepping, if you have a choice)ASUS P6T SE
(or The P6T Deluxe V2 if you want SLI support and/or improved heatsinks. FYI: both versions come with Crossfire support
)3x2GB DDR3 1333 or 1600
(I recommend these: http://www.newegg.com/Product/Product.aspx?Item=N82E16820231230
)Corsair 750TXSamsung Spinpoint F3 500GB
(Consider getting two and setting them up in Raid 0)Radeon HD 5850Antec 900 or 1200TOTAL:
roughly $1,200-1,300 USD depending on local prices and exactly what you get.
If you're going to overclock, get an aftermarket cooler. I recommend the Noctua SE1366, XIGMATEK Dark Knight, or COOLER MASTER V8.
I also recommend you consider a new monitor that will give you 1920x1080 or 1920x1200 resolution to take full advantage of your system's capabilities.
Hope I could help.