Please help!

[Dreaded_Cheese]

Right, I have a budget of £750 to build a new computer (the one I have at the moment is soooooo slow). I will mostly be playing games, and maybe a bit of video editing. Previously I gathered my knowledge from a friend, who built his own computer a few years ago. I have now come to the conclusion that I have surpassed his knowlege.
Anyway....
Here is what I am thinking of getting:

• Gigabyte GA-P35-DS3R (Socket 775) PCI-Express DDR2 Motherboard
• Intel Core 2 Quad Pro Q6600 "Energy Efficient SLACR 95W Edition" 2.40GHz (1066FSB) - Retail
• OcUK GeForce 8800 GT 512MB GDDR3 HDTV/Dual DVI (PCI-Express) - Retail
• GeIL 2GB (2x1GB) PC2-6400C5 800MHz Value DDR2 Dual Channel Kit (GX22GB6400DC)
• Seagate Barracuda 7200.10 250GB SATA-II 16MB Cache - OEM (ST3250410AS)
• Thermaltake VC3000BWS Armour Jr SuperMidi Tower - Black
• OCZ StealthXStream 600w Silent SLI Ready ATX2 Power Supply
• Asus DRW-1814BLT 18x DVD±RW SATA Dual Layer Lightscribe ReWriter (Black) - Retail
• Microsoft Windows Vista Home Premium 64-Bit Edition DVD - OEM - 1Pk (66I-00788)

I have a few questions:

1. Is 600w overkill for the system?
2. Is the GA-P35-DS3R good? (what I mean is do they have any major compatibility broblems?)
3. Would the parts fit easily into the Thermaltake Armour Jr?
4. I intend to get 4GB of ram (2 of the Geil sets), is Geil good (compared to others in it's price band)? should I get 2x2GB instead? What are the benefits if I do?

As this is my first build I probably will not overclock until I understand exactly what to do. Also, these parts prices add up to £735 so unless I could compromise some parts, I doubt I could afford anything more expensive.

 

[Dreaded_Cheese]

Thanks, I feel more confident now. I will probably get a Corsair HX 520W psu instead of that OCZ one. I prefer the idea of a quiet psu, I'd rather not risk another loud psu. The one on the computer I have at the moment is so loud it is hard to concentrate.

I am going to look into overclocking, the prospect of a faster pc is drawing me in.

As I am new to the world of coputer building I don't know whether any new hardware is coming out soon (between now and febuary). would there be any coming out that may interest me? (such as graphics cards) I know that the Penryn is coming out.
The fact is I don't really know where to get information from, this forum is alright, but sometimes I feel a bit left behind, I know what RAID is, I know Mb from Gb, but anything too technical is way beyond me. It's like I have hit a barrier, I know the basics but the jump from this to advanced stuff feels way too far.