Try going to http://www.outpost.com to get a better price on MB and CPU combo that is if your on a budget. I got a pent 4 3.2 retail w/fan 3 year warranty w/ msi MB ( not my choice but works very good) for 199.00
I would recommend from what I have read. and What I have done and have good luck with now. DONT use the sata for your system drive and for your vide drive.
DO NOT use the onboard SATA use a card.
Make sure you have your ram capable of dual channel and set it up accordingly
I would for sure Get a AIW video card possibly a 9800pro 299.00 that is if you can not afford to get a thousand dollar one. I can not.
I am getting SO MUCH MORE faster rendering time close to real time now that I do not have some off the wall generic 128mg PNY card.
I would recommend Larger than a 80gig hard drive for video editing and storage Unless you are unlike me and only work on one project at a time. I currently have 160 and will be upgrading to a 250 SATA this coming week and thinking about adding another 250 next month.
Just my thoughts and experiences over the last few months that I have been trying to soak up everything I can read on this stuff. Since I got a sony dv for my B.D.