yes or you could get only 2 of ATIs new 5000 series cards, they support 3 monitors, however you will need a Displayport to DVI/HDMI or Displayport to VGA adapter for the 3rd monitor on each of the cards.
DP to VGAhttp://www.newegg.com/Product/Product.aspx?Item=N82E16812270279
DP to DVI/HDMIhttp://accessories.us.dell.com/sna/products/Cables/productdetail.aspx?c=us&l=en&cs=19&sku=330-5521
What sorts of things do you plan on using the monitors for? just 2D apps like internet browsers or 3D intensive tasks like rendering?