Yeah I use the Matrox G450 on my machine, and I couldnt be happier with it.
You cant throw in a 10 dollar video card from 6 years ago, but most of the on the shelf cards now adays can handle anything you might need.
The expensive video cards on a PC, usually have really good 3D performance, which wouldnt be needed for something like cubase.
And Matrox dual display cards are quite cheap thankfully.