-> "The entire package."
You've heard of Moore's Law but do you remember Gene Amdahl. He understood that all parts must be in balance since what good would a fast this or that be if the next part couldn't keep up.
But dispensing with that, I still like Tom's Hardware's "Best Video Card for the Money" lists that are updated almost every month. Many gamers have cards slower than what's on the second from the bottom on that list.
I want to buy a new pc for gaming, what is the most important hardware that i have to get for best experience.