If you're ok with sub 60 FPS, you might take a look at this R7 270x from Sapphire. It's got 4GB of VRAM which is much needed when playing on multi-monitor setups. It's an entry level card so odds are though you won't get too close to the VRAM limit. You'll end up maxing out the cards limits beforehand.
IMO, your best bet right now is to give us a budget here on what you're willing to spend and go from there. Also, as Theno said, look at your PSU's wattage because that could also be a limiting factor.