basicaly it redraws portions of the scren and overlaps them so that motion looks smoother.  And you are right it is a reasource hog.

These images are exactly the same where the pixels are vertical or horizontal. What anti-aliasing does is create gray regions around curves and sloped lines to give the illusion they are actually curved. This increases quality and if your computer can support it, I recommend it.

this is exactly, right.

In layman's terms, anti-aliasing blurs the image to make it sharper.

What other way of figureing out how to get the game looking the best vs good performance is there?

Only thing for people in general to remember is that all options arn't equal, textures rarely make a direct diffrence in the speed of frame rendering, just HD caching (jittering, loading delays, texture 'poping') and memory sizes. Detailed shadows are usually the worst performance hogging feature of a game unless your doing 16x AF and 8x AA (which is silly for 99% of people).

I would say trying stuff out is nessesary, especially since no graphics card is the same in each area of operation.

My old graphics card could do geometery FINE, could do most effects FINE. However as soon as you get layered transparancey it just hit a wall, just died. Didn't matter if it was dragonblight or grizzly hills in wow, or a hedge in velvet assassin or whatever - it hit <5 fps. Look up to the sky and 30+.

Gotcha. Well I generally just let a game choose its own settings and only messed with it when i thought wow, that doesnt' seem right. AA doesn't seem to be turned on automatically so sometimes i turn it on, sometimes I don't. I didn't really understand the feature real well enough to think I should be messing with it, but if its something other people tinker with I figure I might try it when i shift to newer games again, most the games I am playing now are pretty well aged except maybe Tropico and some betas.