Niether Poser nor Bryce use Direct3D or OpenGL. That is, a fast 3D video card will not help their performance, they do not offload anything to the hardware accelleration. Having a large screen is useful; if you're buying a monitor as well try to get an 19 inch (or larger) if you can. Your choice of video card will probably depend more on whether you play games on the machine. A TNT2 (suggested above) is a fine card for Poser use, and can be had pretty cheaply nowadays. If you play 3D games, a GeForce card would yield higher framerates.