some friends have told me recently that laptops with nvidia video card in it are failing drastically
models sold in the last 3 years, video card overheats system and detach itself, the system no longer boots, the fix is hard expensive and temporary
this video cards seems to require more air cooling than the laptop gives so a extra fan like this one should be necessary

latest ati cards i have used work perfectly on livecd, installed the last one i used was a hd4830 and it was working fine
the video card in the laptop you choose, i remember a post mentioning problems with the nvidia driver, no idea if it is still a problem with the current driver on repos, maybe you could need to download the driver form nvidia website