Which Card?!

Here's a rough idea of what the other components will be:

CPU: Intel Core 2 Quad Q6600 Kentsfield 2.4GHz 2 x 4MB L2 Cache
http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...

Motherboard: GIGABYTE GA-EP45-UD3L LGA 775 Intel P45 ATX
http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...

RAM: G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066
http://www.newegg.ca/Product/Product.aspx?Item=N82E1682...

Power Supply: OCZ StealthXStream OCZ600SXS 600W ATX12V
http://www.newegg.ca/Product/Product.aspx?Item=N82E1681...

OS: Windows XP SP3

Monitor size/res?

I'm currently using Samsung SyncMaster 226BW with 1680x1050 res.

4870 would be most future-proof, but 5 years is unlikely.

XFX has the best warranty, some cards have a cooler better than the reference.

So the 1GB and 512MB on 4850 and 4870 respectively won't matter much in terms of performance? and in my case, I should go with 4870 because its newer and should be able to handle future os/program/games better than the 4850 (at least from what I understand   ).

I've looked into XFX cards as well, but for the same card.. it's out of my budget. Anyone have experience with HIS or Sapphire warranty and customer service? Please fill me in on those if you can. I've had my computer for 8 years already, and pretty much with no upgrades besides moving to Windows XP. So I'm a bit lost when it comes to choosing parts.  

@JKL: The 4850/4870 are based on the same core and were released at about the same time.
I`d stay away from the cards on your first and fourth links, their coolers do n`t get rid of the heat properly and this can cause problems by overheating other components nearby.
From your list the second one down would be my choice.

What's your current card? Do you play any newer games?

The main reason im planning to get a new computer is because I want to play new games and my current computer will not allow me to do that. lol

my current card is ATI Radeon 9800 Pro.

Get a Q9300 for $170 @ microcenter right now. It's faster and cooler running. (Q6600 is $240 now BTW)

Change the RAM to DDR2 800, save another $20-25.

And change the PSU to PC Power & Cooling Silencer 500W, better quality and $60AR.

Then you should be able to up your video card to HD4870 1GB or GTX260 Core 216, both around $200.

It was my mistake for posting the Canadian pricing.. cause I realized that all the components were from newegg.ca and the video card prices were from newegg.com.

I'm live in Canada so I think the shipping is gonna kill the deal at Microcenter if they even ship to Canada. But, I'd definitely get the Q9300 if its $170US and available at that price here. I checked most places, and Q9300 is still at a higher price than the Q6600.

that's another question I wanted to ask about PSU... I'm really not sure with my rig, how much power I need. As you have suggested, I'm assuming a 500W PSU is more than enough?

If I can save up a few bucks here and there, I'd definitely up my card as to GTX 260! Never been with nvidia before, but I've read some good things.

Q8200 CA$199 bestdirect.ca

GA-EP45-UD3L CA$118 onhop.ca

2x2GB Mushkin DDR2 800 CA$49 newegg.ca

OCZ 600W StealthXStream CA$70AR ncix.com

I'd recommend getting everything from ncix.com if possible. They pricematch, the shipping should be less than newegg.ca, and no PST (unless you're in BC).