Note: He said just built, not built-in. There's one hell of a difference.
Also the non-Pro 9700 is a known troublemaker.
I'm proud to say that until the laptop my father got from his work, that there has never been an Intel based computer in my home. I've never had any problem from an AMD machine.
As far as a new card, if you don't have to upgrade don't, the FX is not enough of an improvement to warrant it. If, however, you have got to get a new card and ATI is out, I would get an FX 5200, simply because it's the cheapest. At the performance level we're talking about, you won't notice a difference until Doom 3 or Half-Life 2 get here.