(NEW SYSTEM) PC for HD Home Video Editing <$900

I've spent the last 3 hours on here and found so much information my brain is looking to explode. You guys are the best and I'm amazed that a website like this exists with so many wise people willing to help.

So, I'm ordering a "Click to configure" computer and I need to stay under $900. The PC will be used for HD Home Video Editing and I'm clueless as to what video card + motherboard to combine. (ATI vs GeForce, etc)

System will have:

Intel Core i5 660 3.33GHz (Dual Core) 4000K
Intel Socket 1156 CPU fan
*MOTHERBOARD?????*
*GRAPHICS CARD??????*
4GB (2x2GB) PC8500 DDR3 1066 Dual Channel
500GB WD 7200 RPM SATA2 UDMA 300 16m cache
LG 22x DVD Recorder Dual Layer +R/RW -R/RW
All-in-One Memory Card Reader Internal Black
Realtek HD digital audio (I have external pro recording interfaces that work as the main audio)
Ethernet network adapter (onboard)
FireWire Adapter Card PCI
PowMax Black Mid Tower ATX Case w/ Front USB
Logisys 400W ATX Power Supply <-- ***Will this be enough???****

As you can see, most of the add ons are basic, I have Win 7 Ultimate 64 Bit that will be installed, and I already have a laptop where I do most of my office work, internet, email, etc so this desktop would be solely for the HD video editing and some audio recording.

Any help would be greatly appreciated. THANKS IN ADVANCE!!

A case for GPU computing: Adobe Premiere Pro CS5 and the Mercury Playback Engine
http://tech.icrontic.com/articles/ [...] ck-engine/

So assuming u want to leverage Mercury Playback engine @ $673AR (makes playing games an option as well)

else just stick to the 880G IGP ^^

Maybe I should rephrase. I'm not doing 1080p. Likely 720 or 1080i at most. Nothing pro. Just making sure life memories from our camcorder can be edited and sent out to family. And recording sports games to have a library of them at home. Most likely 720P would do.

Thanks for the responses so far.