Re: AA question.
Stick to Anisotropic filtering set at 16x
As for the two other options, those are the AA options for smoothing sharp edges in games.
You really only need it when your playing at a resolution below your monitor's native resolution, but it makes the game look better either way.
If I remember correctly, MSAA is better on Nvidia GPU's so I would stick to that. I have a HD4870 and I have a few different option's for AA as well. Edge-detect for me, MSAA for you.
If your running at the native resolution of your monitor, then you only really need 2x or 4x samples of MSAA.
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