[nVidia]'s line of graphics cards. Pretty much everything they make now is a GeForce something-or-other. They're up to the GeForce7xxx? right now.
In any case my GeForce 6800GT, though now a bit dated, still manages to hold its own for everything I want to do. I play QuakeIII and WarcraftIII (using WineX) and they're both nice and silky smooooth on my rig so I really don't have anything to complain about.