What benefit does upping the AA give you?
When you look at the outline of anything on screen--the characters, the edge of buildings, and most conspicuously, cable lines--you'll since "jaggies," slight imperfections in the outline, so that a straight line isn't totally straight, a curve isn't perfectly curvy.
AA will smooth out those jaggies. It'll bring down frame rate a lot, but when your system can handle it, as it seems yours can, definitely go for it.
Example:
