Opinions on this econo PC

I have built a few PC's in the past, way back in the day, and never had any problems. Since I have been out of the loop for a while I would like opinions on the following economy setup.

APPROXIMATE PURCHASE DATE: 1 week
BUDGET RANGE: Under $1,000
SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: Family/Home video editing, Audio/photo conversion, Light CAD, Light gaming (e.g.: Cities XL), Surfing the internet, Watching movies
PARTS NOT REQUIRED: Keyboard, Mouse, Speakers, OS
PREFERRED WEBSITE(S) FOR PARTS: Newegg (preferred), Tiger Direct, CDW, Comp-U-Plus, M-Wave, Microcenter, etc
COUNTRY OF ORIGIN: USA
PARTS PREFERENCES: None really
OVERCLOCKING: Maybe
SLI OR CROSSFIRE: Doubtful
MONITOR RESOLUTION: Not to concerned
ADDITIONAL COMMENTS: None

This is what I have picked out to date:
CPU: AMD Phenom II X2 550 Black Edition 3.1GHz http://www.newegg.com/Product/Prod [...] 6819103680
MB: GIGABYTE GA-MA785G-UD3H http://www.newegg.com/Product/Prod [...] 6813128395
Memory: Kingston HyperX T1 Series 4GB (2 x 2GB) 240-Pin DDR2 1066 Dual Channel Kit Desktop Memory http://www.newegg.com/Product/Prod [...] 6820104098
Case: COOLER MASTER Centurion ATX Mid Tower Computer Case 460W Power Supply http://www.newegg.com/Product/Prod [...] 6811119208
HD: WD Caviar Black WD7501AALS 750GB 7200 RPM 32MB SATA 3.0Gb/s 3.5 http://www.newegg.com/Product/Prod [...] 6822136283
DVD/CD Drive: PLEXTOR SATA DVD/CD Writer LightScribe http://www.newegg.com/Product/Prod [...] 6827249051
Card Reader: Nippon Labs Internal Card Reader All In One Card Reader/Writer with USB2.0 & ESATA http://www.newegg.com/Product/Prod [...] 6820816003
Monitor: Acer X233Hbid Black 23" 5ms HDMI Full 1080P Widescreen LCD Monitor 300 cd/m2 40000:1 (ACM)
http://www.newegg.com/Product/Prod [...] 6824009163

I plan to upgrade the RAM to 8gb and add a HD the following month. After that I'd like to add a GPU similar to an ATI 5000 series and a Bluray player/burner. I figure I can always upgrade the PSU if needed. My biggest question is DDR2 vs DDR3. All thoughts and opinions appreciated.

Yeah, I didn't see much more than a 10% increase in performance from the research I did, and the $200 I save will pay for about half of my video card.