As for the ATI question: Ati drivers are allright, no worse than Nvidia's, but its Ati's control panels that are the problem.
Their latest ones are severely crippled. They give MUCH less functionality than old versions, such as no more Smart Gart control.
Also, to make it worse, it requires an active connection to the internet so it can phone home. If it doesn't get one, it doesn't even load. It just patiently sits hidden away in memory until it can get one.
I reccomend Omega Drivers:
http://www.omegadrivers.net/
I use Ati's drivers, with Omega's control panel. Works brilliantly.