It's better to buy a laptop with i5 2430 and a GTX 560m or 570m rather than an i7 2670QM with a lower graphics card like the 555 3 GB or Radeon HD6770M 2GB, right?
According to the new article about Skyrim here CPU plays an important role but still a better graphics card should give better FPS, right? By the way, at what FPS a game is smooth without any lags or noticeable jerks? Is it the standard 60 FPS, or would 40 be enough?
Yes. GPU plays an important role in games. But there are certain games like skyrim where CPU also plays a role and in this situation a quad core helps out a lot.
Given that a standard refresh rate of monitor is 60Hz, the maximum possible frame rate above which you wont notice any lag/jerk is 60. But generally anything above 30 fps is really playable and lag free as long as your CPU is fast enough to support.