The Acer with the 9600M GT looks the best, it has 512MB dedicated RAM on the graphics card alone, the rest only have 256MB. That can easily handle any current game, but its a 17" wide-screen. Too big?? Also its 3.8kg, much heavier than some of the others, but it is top spec.
Nvidia don't have many better than the 9600 GT, whereas the 3400 series is pretty basic in terms of the ATI catalogue.