Here's something I was looking at for a home PC, but it would totally rock for what you are doing.
Mobo:
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131666
CPU:
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115066&cm_re=six-c...
RAM:
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231381&cm_re=ddr3_...
For $1580 you have the main components.
You could probably shave some on components, like getting a little less CPU, or go for 6GB RAM for starters. But I think this would be some time before needing an upgrade. You could get away with a little less of a graphics card, since you don't mention using PP much.
