Which graphic card 4 my laptop?

Easy, go with the one with the first one with the GF9600M GT, the difference between it and the HD4570 is much larger than that of the two CPUs which is only 100mhz difference.

The pixel shader model improvement while handy will either not be very usable by the HD4570 (where it's an image changer) or else not provide much of a boost to be notable (the improvement in performance will take it from very low to low, and may do little to improve it versus the competition). For entry level cards the benefit isn't as attractive as for mid-range cards which have a better chance of using the features for greater benefit.

That's a pretty generalized statement, especially when there are a bunch of laptops can outperform many desktops. It would be like saying don't by a desktop based on the fact that DELL desktops suck, thus all desktops suck. In this case it's more of a question 'if gaming is your focus, you would likely need a more powerful laptop or be better served by a desktop', but that's far different than 'don't buy a laptop'.

Usually people ask about gaming when they've already figured out their other need for a laptop, and just want to add the gaming component.

As for the resolution, personally I'm a fan of 1920x1200, because it gives you alot of desktop space and then allows solid 4:1 pixel scaling @ 960x600 for tough games, but unfortunately in this case with the other being 1600x900, that scales to 800x450 which is not as creat an experience, but actually might be better for performance on tougher games.

It's all a question of balance.

Ah, I misunderstood what you meant by decent games. Usually people mean new, shiny games rather than just interesting ones.

On the subject of gaming on laptops, it is just not a good option unless you have tons of money. Not a good long term investment by any means.