Hmmm... tough choice.
The $400 for all three pretty much throws i7 option out. (i7 = $290; good X58 board - ~$190+ ).
This is probably one of the good/best deals for Phenom 2:http://www.newegg.com/Product/ComboDealDetails.aspx?ItemList=Combo.182472
Phenom II X4 810 + Gigabyte 790X board
On the Intel side:
P45-UD3P ($115 after MIR) + Q6600 ($214) or E8400($165)
Total: $329 (w Q6600) or $280 (w E8400)
The price difference all comes down to the RAM. Choosing between the Phenom II and the Intel Q6600/E8400 is up to you.
Imo, considering that LGA775 is EOL I would get the Phenom 2. Or if you are on a very tight budget P45-UD3P + E8400.
Best bang for buck (imo)
P45-UD3L($93) + E5200($70) or E8400($165)
Total: $163 (w E5200).
All prices are Newegg prices.