Proposed i7 based build - Seeking advice

Hi there,
This is my first post on TH so hello and thank you for reading.

APPROXIMATE PURCHASE DATE:
At the moment im planning on building the PC around january of next year mainly to squeeze price drops out of the components and because ill have work round that time.

BUDGET RANGE:
Basically around NZ$2,500 as im from New Zealand, (prices mentioned are in NZ$)

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT:
Gaming, Burning DVD's, Surfing net etc.

PARTS NOT REQUIRED:
Keyboard, Mouse, Speakers

PREFERRED WEBSITE(S) FOR PARTS:
www.pricespy.co.nz is what i will be using to get the cheapest parts in NZ as ive used it before for other builds and its quite reliable. It collects prices from NZ online and retail stores.

PARTS PREFERENCES:
Understand im not a fanboy of any brand but obviously i will be using the Intel Core i7, preferably a gigabyte or ASUS motherboard, preferably G.Skill RAM etc. Oh and i would prefer nVidia over ATI simply because of more frequent driver releases (Believe me, i respect the competition that ATI brings against nVidia's proposed monopoly. It is beneficial to all gamers)

OVERCLOCKING: Maybe in the future, not something too important to me right now.
SLI OR CROSSFIRE: Again, Maybe in the future.

MONITOR RESOLUTION: 1680x1050 (Samsung Syncmaster T220)

ADDITIONAL COMMENTS: I have selected a few components already but cant decide amongst a few of them. They are:

CPU: Intel Core i7 920 LGA1366 [$446.95]

Motherboard: GIGABYTE EX58-UD5 [$447.00]
(I was thinking of going for the ASUS P6T Deluxe, but it is around $90 more expensive and i dont think i need the extra features. Besides im not happy with ASUS at the moment as ive had motherboard problems before with the P5KC)

Graphics: nVidia GTX 285 1GB [$519.24]
(Im aware of the 5xxx series of ATI cards but i think id rather stick with the 285)

Storage: WD Velociraptor 150GB [$244.00]
(I think i may actually go with the $80 seagate barracuda 500GB because its a fraction of the price and unless im mistaken, beats the velociraptor in the performance charts on this website.)

Memory: G.SKILL 6GB Tri-Channel kit DDR3-1333CL9 [$220.00]
(i like G.Skill. They make good ram at reasonable prices.)

PSU: PC Power and Cooling Silencer 750W [$239.00]
(Definitely wanted a good PSU and ive read good reviews on this one, but im a bit annoyed the reviews make the point of it not living up to its 'Silencer' name. Any suggestions for a similar quality and price unit?)

Case: Antec 900 [$239.00]
(My friend has one so ive seen them up close. Alot of people dont like them but i think the airflow is very good. I might do some cable management cutting and a paint job maybe, but i wont post it all over the internet on mod sites because theres enough of them )

Optical drive: Pioneer DVR-215BK [$77.00]
(Good review on cdfreaks.com, want a reliable burner to transfer files between PC and DVD.)

Display: 22" Samsung Syncmaster T220 [$359.00]
(believe me, i researched alot of display threads and reviews to find a reasonable lcd for gaming. what i found out is that a CRT is allmost allways better than a lcd for gaming with response times, contrast ratios, no blurring etc... but i think i found a monitor i can use. Bare in mind ive used a 17" crt for my whole life.)

So thats basically it as far as the components im deciding between goes. Please feel free to comment and give advice on these choices, or suggest other components with similar prices/quality and remember i probably dont have as many parts available as in the US, and i dont think i can get 'rebates' like in the US. Please tell me if ive missed an important piece of info. Thank you for reading and sorry for spelling mistakes.

Probably windows 7 as i wont be putting it together for quite some time. Id rather have an nVidia card to possibly SLI with in the future over crossfire. Why should i choose a 5870 over a gtx 285?

Will you regret the 285 in 2 years because its only DX10 and many of the latest games have implemented DX11 features?

The 5850 is cheaper and a bit faster, the 5870 is lots faster and not much more. Even ignoring DX11, from a price/performance standpoint its overpriced right now.