So, you are suggesting that I use a 750 W PSU? Is that minimum? Also, I may do the gtx 460s in sli sometime in the future. Will I need a higher wattage PSU for that?
You will want at least a high quality 650W power supply. That 750W one would be more than good enough, but the 600W ModXstream in your build would not.
This XFX 750W power supply for
$90 (with the promo code XFXPOWER and after a $20 rebate)
would also be more than enough. It is also very high quality (80 plus silver certified, modular) and highly regarded.
I see that you are shopping in Canada.
This Cooler Master one would suffice for $103
This Corsair one would be much better for $120
after a $20 rebate:http://ncix.com/products/index.php?sku=35156&vpn=CMPSU-850TX&manufacture=Corsair&promoid=1015