Totally agree with Robrich, if you use your system for working at home, using 3D apps, AA and FSAA means nothing to you at all. OpenGL is king for 3D applications.
Take also into account ATI's bad driver rep (which has improved vastly since the earlier Radeons) and Nvidia's comparatively better stability, toss in ATI's current position as gaming king of the framerate. Its a tough toss up. For me I would go for the Nvidia Ti4600, since its price has gone down a lot since the release of the Radeon 9700 Pro.
But bottom line is, what do you see yourself using it for? D3D gaming? OpenGL gaming? Text? Video? The choice between both will be easier if you can decide that part yourself.
Good Luck!