I went with a Caldwell 6-9" bipod on my Ruger Gunsite Scout. Admittedly I didn't do TON of research on bipods before I got mine. I just went to Walmart and saw the Blackhawk ones, and compared it to this Caldwell one at Dick's Sporting Goods.
I was totally surprised by how easy this thing is to put on and take off! It attaches on to the sling swivel stud and you just turn one knob to tighten it down. It's really sturdy, and it weighs 12 Oz. I think I paid $30 something for it.