Multiple video cards, one monitor

[antareus 0]

Could I hook up a Matrox Millenium PCI and a GeForce 2 to a single monitor, using the Millenium for 2D and the GeForce for 3D? Several people have commented that the Geforce is notorious for poor 2D quality at higher resolutions. The monitor I'm looking to get is the Sony G400, which has two inputs.