I use a Shuttle XPC (http://www.newegg.com/Product/Product.aspx?Item=N82E168...)as my video editing machine. I have an Opteron 1354 CPU, 4GB DDR2 RAM, a FireGL V3600 PCI-E GPU, 2 Samsung monitors (205BW), 2 HDDs (500GB and 640GB), and a Plextor DVD-RW. It performs great, is very quiet, and gets the job done well.
I recommend the XPC with lower wattage Phenom II/Athlon II X4 CPU (94W or less). I would also suggest a dual monitor config to allow for editing on one screen and viewing on the other.
Keyboard, mouse, HDDs, and BD/DVD burner up to you. I would also recommend Win 7 Pro 64-bit as your OS.
I have a quad core Opteron 1354 in mine right now. I pound the CPU pretty hard and NEVER have a heat problem. Absolutely not a problem as the included HSF (with heatpipes) is very efficient AND quiet. Your call, but makes a great video production system for me, I highly recommend it given your requirements. Good luck!