Hello and welcome to geeksto go.
VGA, find any Nvidia that supports SLI in GT code number.
SLI is only for the very high end or people that have serious money to burn, there is no point in paying double the money for 30% of a performance gain, the 8500 and 8600 models are junk.
There is a ATI DX10 card out, its 450$, the budget-mid range are coming out in mid July.
No, ATI's cards will work just as well with Intel as it would with AMD, this may change next year because Intel is entering the graphics card department, but for now neither are competing, matter of a fact Intel support ATI more then Nvidia as Nvidia has denided Intel technology for the motherboard chipsets forcing them to work with thier competitor for now.
If you can't spend more then 200$ wait till christmas time, save up, because your going to need both a new PSU and a GPU. Current sub 200$ cards won't run DX10 gaming worth a darn at all, people are reporting frame rates below 15FPS, though I don't know what settings they were gaming at. Also newer and better cards will be out then forcing current ones down, if you can wait I suggest it, because 200$ simply isn't enough for the future when it comes to graphics cards, not to meniton the additional costs associated with the purchase of a PSU. I can't recommend anything below the 8800GTS 320MB as this point in time for DX10 cards.
I'm canadian as well, I suggest taking a loot at these sites, they offer free shipping every now and then.
Edited by james_8970, 20 June 2007 - 11:10 AM.