Hey, mostly finished my build and got some extra cash again looking for a Gpu to polish it off for gaming and everyday use looking around the 200-300 Canadian dollar mark.
This card will give you plenty of options, including purchasing an identical one in a year or so when the price has come down $100 or more. I suggest going for it because right now it's hard to argue with the features, and the fact this card will kill any game you throw at it on 1 monitor no matter how large.
I've done A TON of research. Nvidia is the way to go for an intel prosessor, especially the i5. I STRONGLY RECCOMEND reading this review. http://www.tweaktown.com/reviews/4779/msi_geforce_gtx_670_power_edition_2gb_overclocked_video_card_review/index18.html
Just scroll down to the bottom of the page and you can skip to the reviewed parts you want. Anything above 90% is a solid card. Anything more than 2GB or ram you won't notice the difference unless using multipe monitors, and if that happens, purchasing another one of these will absolutely kill any game for the next 3-4 years and still be decent after that.
Since we Canadians have to pay a good extra chunk in taxes, you won't get a 660ti or 7950 under $300, you could try to sqeeze them it but it will end up a handful above your price point. Thus, I'd recommend: