Very good work. Few suggestions, but first off...nope. You don't need a dedicated GPU. And if you don't game and if/when you do it sounds as if it might just be casual, I'd just start off the Ivy integrated HD4000.
CPU: Intel Core i5-3570KIf time is critical in your video work, then step up to HT and get the 3770k instead. You can find what HT does in video crunching here
MOBO: ASRock Z77 Extreme4Nice and solid board with great reviews. If you're not going to OC hard then look into the Asrock Pro4. Both it and the 3770k can be had for $330 at MicroCenter in their bundle deal. I've really been impressed with the past half dozen or so Asrock boards. At the price:performance I'd easily take them over Asus any day.
PSU: CORSAIR Enthusiast Series TX650Good psu, but the Seasonic X series is better. Even so, you don't need 650w if no GPU. Aim for a 500w unit, like [url=http://www.newegg.com/Product/Product.aspx?Item=N82E16817171038&nm_mc=EMC-IGNEFL110812CO&cm_mmc=EMC-IGNEFL110812CO-_-EMC-110812-Index-_-PowerSupplies-_-17171038-L08Bthis $35[/url] Coolermaster.
RAM:CORSAIR Vengeance 8GBMeh! You can do much, MUCH better with these low voltage Samsungs or if you want to go 2x8 then this ultra high performing Mushkin
HDD: Seagate Barracuda ST31000524AS 1TB 7200 RPMA 1.5TB Barracuda is $70, the 2TB is $90, and the 3TB is $120...it's king!
Monitor: Acer S231HLbid Black 23" 5ms HDMI LED (Is this ok??)This 26" Hanns-G is a great buy at $170 shipped if you want to stay at 1080p. Personally I'd crank it up to 1200 or even 1440 for video editing.
Optical: ASUS 24X DVD BurnerBetter is this Samsung
Case: Corsair Carbide Series 300RIf you say so. I was woefully unimpressed with it in person
OS: Windows 7 64bitGo Pro so you'll have access to >16GB of memoryLastly, you simply must pick up an ssd for the OS and file swapping. Look no further than the Samsung 830/840 or the Crucial M4 in either the 128 or 256 flavor...$70 and $160 respectably.