Mmmmm.... well, if you'll look at my post above you'll see I'm using Bootcamp, not parallels. I seriously doubt it would run at all in parallels, due to the fact that it has no meaningful (at least from a gamer's standpoint) hardware support.
As to what settings I use in Bootcamp, I've got it at 1280x768 resolution, Large texture size, all of the actor fade settings right in the middle, outside view distance maxed, HDR on, and all of the little effects (water detail, reflections on water and glass, etc) turned to either on (for the on/off ones) or high (for stuff like blood decals, water detail, etc, with multiple settings).
The only real sacrifice I make is in toning down the self-shadows (because I think they looks stupid, not for performance reasons) and taking the shadows from trees and the shadows on grass down to about 1/4 the way up the slider.
I get good, strong performance. I get the occasional chug, but that is usually related to something else, like me being an idiot and playing until 4 AM. It's time to go to bed when then AV scanner starts eating up your performance.
Have I seen better? Heck yes, usually from my friends' massive gaming towers. Do I get an enjoyable experiance from a VERY portable laptop that is running an OS that it was never designed for? Oh yeah.
