For anyone needing or wanting four displays driven by one card, I just successfully hooked up my fourth display to an Asus GTX 670. I needed a Displayport to DVI adapter for my fourth display. The HDMI port is connected to a Plasma TV, but I'm sure I could have hooked up another monitor instead if I wanted.
By the way, I was concerned about using a long (50 feet) HDMI cable to the TV, but it works great. In reply to an earlier poster, I could edit on the plasma TV if needed, but I'm only using it for display. In my opinion, an HDMI cable is the ultimate method for getting content from a computer and/or internet to a TV.
The HDMi 1.4 cables that are heavily shielded are exactly what you want for that kind of cable run. I have a setup at my Father in Law's house with 50 Foot HDMI 1.4 cable and it runs great. It's also what I recommend to our clients since that is really far outside of DVI or Displayport's spec.