The bipod is one of the most important pieces of equipment a precision shooter uses. Harris Bipods have served well for a long time, and are the standard bipod for military and police. They are affordable, available, and fairly sturdy. I was in Iraq in 2007 and came across the Atlas Bipod on the rifles of another unit. It's one of those products that after seeing one you will never be able to go back to the old stuff. The Atlas is lighter than comparable Harris models, uses superior materials, is considerably less bulky, and is much more adaptable to a variety of shooting conditions.
The fact that the Atlas has no exposed springs that slap open is also a big plus. The Atlas can lock out straight to the front or 90 degrees straight down similar to Harris. The similarities end there, with the Atlas affording the opportunity to lock at 45 degrees for a lower profile and straight to the rear as well. This is useful for shooting positions in a dynamic environment where dropping bags is impractical but the standard Harris would be too tall if deployed. The option to lock to the rear is especially useful on shorter rifles (SR25 EMC, SCAR-H, SPR, shortened bolt guns) as you can move the bipod to it's proper forward position and it not stick past the muzzle.
The version pictured takes the Larue LT171 mount, which is my favorite option. There is also a version that use a standard clamp-and-screw arrangement if you do not need the option of rapid installation or removal. A version with an ARMS 17S already installed is available, but we all know the deal with ARMS. You wouldn't mount a Schmidt and Bender with duct tape so why mount your bipod with a hunk of pot metal shit?
The Atlas costs $219.00 from Bauer Arms (http://www.bauerarms.com/) with either the plate for the LT171 or the 1913 clamp. I bought mine from them and it was a great experience. Other people sell them to include Botach...stay away from them. It sounds pricey but a comparable equipped modified Harris costs approximately $275 and it still comes with all the Harris issue and none of the Atlas functionality.
Atlas has a new version with a new locking system for the legs offering a much larger range of available positions for the legs as well. Check them out at http://www.accu-shot.com/.