A lower screen res with AA enabled should look a lot better, esp if you ensure the refresh rates are optimal. If you're using a GF4 then you should find QuinxAA and Aniso offer by far the best quality and speed, better than 4x without Aniso and identical looking with Ani. You may find you can get 1280x1024 QxAA & Ani at a comparable FPS to 1024x768 4xAA and 1600x1200 noAA.